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MCQ Questions for Class 10 Science Chapter 9 Heredity and Evolution

Heredity and Evolution Class 10 MCQ Questions With Answers

Question 1.

Which of the following statement is incorrect?

(A) For every hormone there is a gene.
(B) For every protein there is a gene.
(C) For production of every enzyme there is a gene.
(D) For every molecule of fat there is a gene.
Answer:
(D) For every molecule of fat there is a gene.

Explanation:
Hormone and enzymes are proteins and formation of any particular protein is controlled by a particular gene. Hence, all other options are correct.

Question 2.

If a round, green seeded pea plant (RRyy) is crossed with wrinkled, yellow seeded pea plant, (rrYY) the seeds produced in F, generation are

(A) round and yellow.
(B) round and green.
(C) wrinkled and green.
(D) wrinkled and yellow.
Answer:
(A) round and yellow.

Explanation:
As roundness and yellow colour are shown by capital letters in the genotype, so they are dominant traits. In FI generation, only dominant traits are expressed.

Question 3.

The maleness of a child is determined by

(A)the X chromosome in the zygote.
(B) the Y chromosome in zygote.
(C) the cytoplasm of germ cell which determines the sex.
(D) sex is determined by chance.
Answer:
(B) the Y chromosome in zygote.

Explanation:
Y-chromosome in zygote means that the zygote would develop into a male I j child.

Question 4.

A zygote which has an X-chromosome inherited from the father will develop into a

(A) boy.
(B) girl.
(C) X- chromosome does not determine the sex of a child.
(D) either boy or girl.
Answer:
(B) girl.

Explanation:
A zygote with XX chromosomes in the 23rd pair would develop into a girl child.

Question 5.

From the list given below, select the character which can be acquired but not inherited.

(A) colour of eye.
(B) colour of skin.
(C) size of body.
(D) nature of hair.
Answer:
(C) size of body.

Explanation:
Traits in other options are always inheritable traits.

Question 6.

Two pink coloured flowers on crossing resulted in 1 red, 2 pink and 1 white flower progeny. The nature of the cross will be

(A) double fertilisation.
(B) self-pollination.
(C) cross fertilisation.
(D) no fertilization.
Answer:
(C) cross fertilisation.

Explanation:
As it is mentioned in the question that two pink coloured flowers were crossed, thus it is cross fertilization.

Question 7.

A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because

(A) tallness is the dominant trait.
(B) shortness is the dominant trait.
(C) tallness is the recessive trait.
(D) height of pea plant is not governed by gene’T’ oi’t’.
Answer:
(A) tallness is the dominant trait.

Explanation:
This is a case of monohybrid cross, in which all the progenies in the FI generation show dominant character. Hence, tallness is the dominant trait.

Question 8.

The number of pair (s) of sex chromosomes in the zygote of humans is

(A) one.
(B) two.
(C) three.
(D) four.
Answer:
(A) one.

Explanation:
The sex chromosomes are in the 23rd pair.

Question 9.

In evolutionary terms, we have more in common with

(A) a Chinese school-boy.
(B) a chimpanzee.
(C) a spider.
(D) a bacterium.
Answer:
(A) a Chinese school-boy.

Explanation:
In evolutionary terms, we have more in common with a Chinese school boy as both are humans and belong to same species.

Question 10.

The theory of evolution of species by natural selection was given by

(A) Mendel
(B) Darwin
(C) Morgan
(D) Lamarck
Answer:
(B) Darwin

Explanation:
The theory of evolution of species by natural selection was given by Charles Darwin.

Question 11.

The theory of inheritance of acquired characters was given by

(A) Mendel
(B) Darwin
(C) Morgan
(D) Lamarck
Answer:
(D) Lamarck

Explanation:
The theory of inheritance of acquired characters was given by Lamarck.

Question 12.

If the fossil of an organism is found in the deeper layers of earth, then we can predict that

(A) the extinction of organism has occurred recently.
(B) the extinction of organism has occurred thousands of years ago.
(C) the fossil position in the layers of earth is not related to its time of extinction.
(D) time of extinction cannot be determined.
Answer:
(B) the extinction of organism has occurred thousands of years ago.

Explanation:
Newer fossils are deposited in layers above older fossils.

Assertion and Reason Based MCQs

Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.
(A) Both A and R are true and R is the correct explanation of A.
(B) Both A and R are true but R is NOT the correct explanation of A.
(C) A is true but R is false.
(D) A is false and R is true.

Question 1.

Assertion: A geneticist crossed a pea plant having violet flowers with a pea plant having white flowers, he got all violet flowers in first generation. Reason: White colour gene is not passed on to next generation.

Answer:
(C) A is true but R is false.

Explanation: The gene for violet flowers is dominant over the gene for white flowers so that only the violet gene is expressed as violet flowers in the first generation.

Question 2.

Assertion (A): Mendel chose a number of varieties of garden pea as plant material for his experiments.
Reason (R): Garden pea has well defined characters and is bisexual.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Mendel chose garden pea as plant material for his experiment because garden pea plants were easily available they grow in one season fertilization was easy.

Question 3.

Assertion (A): In humans, males play an important role in determining the sex of the child.
Reason (R): Males have two X chromosomes.

Answer:
(C) A is true but R is false.

Explanation:
Sex of a child is dependent on the type of the male gamete that fuses with the female gamete. Human beings possess 23 pairs of chromosomes. Out of these, 22 pairs are known as autosomes, while the remaining one pair comprises sex chromosomes (XX in females and XY in males). At the time of fertilisation, the egg cell fuses with the sperm cell, resulting in the formation of the zygote. If the egg cell carrying an X chromosome fuses with the sperm carrying an X chromosome, the resulting child would be a girl. If the egg cell carrying an X chromosome fuses with the sperm carrying a Y chromosome, the resulting child would be a boy.

Question 4.

Assertion (A): Learning a skill such as dance and music is an acquired trait.
Reason (R): Acquired traits develop in the life time of an individual and do not pass to the progeny.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Trails which develop in the life time of an individual and do not pass to the progeny are called acquired traits. Learning a skill such as dance/music/loss of body parts/’ weight etc are example of acquired traits.

Question 5.

Assertion (A): Traits like eye colour or height are inherited traits.
Reason (R): Inherited traits are not transferred from parents to young ones.

Answer:
(C) A is true but R is false.

Explanation:
Eye colour and height are genetically inherited traits, as these are expressed by genes. Inherited traits are the traits which are transferred from parents to young ones. Acquired traits are the characters that are acquired by the individual during its lifetime. These traits cannot be inherited. For example, if a wrestler develops large muscles due to his training program that does not mean it will be passed on to his offspring.

Question 6.

Assertion (A): Fossils are remains of dead organisms.
Reason (R): It is helpful in study of evolution.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Fossils are remains of hard parts of the dead organisms in the strata of earth. It help in tracing evolutionary pathways.

Question 7.

Assertion (A): Wings of butterfly and wings of bat are analogous orgAnswer:
Reason (R): Analogous organs have different origin and structural plan but same function.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Wings of butterfly and wings of bat though they perform similar function, they have different origin/basic structure. Hence, they are known as analogous orgAnswer:

Question 8.

Assertion (A): Speciation is the process of formation of a new species from a pre-existing one.
Reason (R): Mutation plays a role in speciation.

Answer:
Option (A) is correct.

Explanation:
Speciation is an evolutionary process by which new species arise. One of the factors that lead to speciation is mutation.

Question 9.

Assertion (A): Natural selection is the phenomenon by which the nature selects those species which possess survival advantage over the other species.
Reason (R): According to theory of natural selection, there is struggle of existence within the species of a population for the environmental resources and their struggle leads to survival of certain organisms and elimination of the less competent species.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Natural selection is the phenomenon by which the nature selects those species which possess survival advantage over the other species. According to theory of natural selection, there is struggle of existence within the species of a population for the environmental resources and their struggle leads to survival of certain organisms and elimination of the less competent species.

Case-Based MCQs

Attempt any 4 sub-parts from each question. Each sub-part carries 1 mark.

I. Read the passage and answer the following questions from Question 1. to Question 5.
In a cross between plants with purple flowers and plants with white flowers, the offspring of Fj generation all had white flowers. When the Fj generation was self-crossed, it was observed in the F2 generation that out of 100, 75 flowers were white. Make a cross and answer the following questions:

Question 1.

The above cross is known as:

(A) Monohybrid cross
(B) Dihybrid cross
(C) Test cross
(D) Back cross
Answer:
(A) Monohybrid cross

Explanation:
A cross between two plants, which differ in only one pair of contrasting characters is calld monohybrid cross. In this cross, F2 phenotypic ratio is 3 :1 and genotypic ratio is 1: 2 :1.

Question 2.

In a monohybrid cross between two heterozygous individuals, percentage of pure homozygous individuals obtained in F₁ generation is ?

(A) 25%
(B) 50%
(C) 75%
(D) 100%
Answer:
(B) 50%

Explanation:
In a monohybrid cross between two heterozygous individuals, percentage of pure homozygous individuals obtained in F, generation is 50 %.

Question 3.

Which of these is not the genotype of F progeny?

(A) WW
(B) Ww
(C) ww
(D) Wp
Answer:
(D) Wp

Explanation:
Genotypes of F₂ progeny are WW, Ww, ww.

Question 4.

The ratio of ‘White: Purple’ flowers in the F₂ generation is

(A) 3:1
(B) 1: 2
(C) 1 : 3
(D) 2 :1
Answer:
(A) 3:1

Explanation:
Ratio between White : Purple flowers are 3:1.

II. Study the given cross showing self pollination in F₁ and answer the following questions from Question 1. to Question 4.

Question 1.

The missing blank in the above cross is:

(A) RrYy
(B) RRYY
(C) RryY
(D) rryy
Answer:
(A) RrYy

Explanation:
RrYy (Round Yellow) is the I missing blank in the above cross.

Question 2.

The combination of characters in the F₂ progeny are:

(A) Round Yellow: Round Green: Wrinkled Yellow: Wrinkled Green
(B) Round Green : Round Yellow : Wrinkled yellow : Wrinkled Green
(C) Round Yellow : Round Green : Wrinkled Green: Wrinkled yellow
(D) Round Green : Round Yellow : Wrinkled yellow : Wrinkled Green
Answer:
(A) Round Yellow: Round Green: Wrinkled Yellow: Wrinkled Green

Explanation:
In F₂ generation, the combination of characters is Round Yellow: Round Green: Wrinkled yellow: Wrinkled Green.

Question 3.

The ratio of the combination of characters in the F₂ progeny is:

(A) 3: 1
(B) 1: 2: 1
(C) 1 1: 1
(D) 9 : 3 : 3 :1
Answer:
(D) 9 : 3 : 3 :1

Explanation:
The ratio of the combination of 8 characters in the F₂ progeny is 9: 3: 3:1.

Question 4.

A Mendelian experiment consists of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic make-up of the tall parent cod depicted as

(A) TTWW
(B) TTww
(C) TtWW
(D) TtWw
Answer:
(C) TtWW

Explanation:
All progeny bore violet flower, so they all must have gene for violet flower. As violet colour appears in hybrids thus it must be the dominant character. So, white flowered plant should have ww genes to show recessive white character. It indicates that all progenies got allele W (violet colour) from tall-violet flowered plant, thus its all gametes should have this allele. To serve the purpose plant must have WW genes. But, tallness was found in 50% progenies thus half of its gametes contained T gene and other half contained t gene. Inclusively, the tall plant had TtWW genotype.

III. Read the given passage and answer any of the four questions from Question 1. to Question 5. given below:
Seema crossed pure breed pea plants having round-yellow seeds with wrinkled green seeds and found that only A-B type of seeds were produced in the F, generation. When F, generation pea plants having A-B type of seeds were cross-breed by self pollination, then in addition to the original round yellow and wrinkled green seeds, two new varieties A-D and C-B types of seeds were also obtained.

Question 1.

What are A-B type of seeds?

(A) Round -yellow
(B) Round- green
(C) Wrinkled-yellow
(D) Wrinkled-green
Answer:
(A) Round -yellow

Explanation:
A-B type of seeds are round in shape and yellow in colour.

Question 2.

A and B are……… traits.

(A) dominant
(B) recessive
Answer:
(A) dominant

Explanation:
A-B type is dominant traits.

Question 3.

A-D are……… and C-B are ……….. type of seeds.

(A) Round green and wrinkled yellow respectively
(B) Round yellow and wrinkled green respectively
(C) Wrinkled green and round green respectively
(D) Wrinkled green and round yellow respectively
Answer:
(A) Round green and wrinkled yellow respectively

Explanation:
A-D is round-green while C-B is wrinkled- yellow.

Question 4.

Which one of these will be produced in minimum and maximum number in the F₂ generation?

(A) A-B
(B) A-D
Answer:
(A) A-B

Explanation:
A-B is produced in maximum number while A-D will be produced in minimum number.

Question 5.

The above cross is known as

(A) Monohybrid cross
(B) Dihybrid cross
(C) Test cross
(D) Back cross
Answer:
(B) Dihybrid cross

Explanation:
A cross between two plants, which differ in two pairs of contrasting characters are called dihybrid cross.

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 9 Heredity and Evolution Read More »

MCQ Questions for Class 10 Science Chapter 8 How do Organisms Reproduce?

MCQ Questions / Prasanna

How do Organisms Reproduce? Class 10 MCQ Questions With Answers

Question 1.

Reproduction is essential for living organisms in order to

(A) keep the individual organism alive.
(B) fulfill their energy requirement.
(C) maintain growth.
(D) continue the species generation after generation.
Answer:
(D) continue the species generation after generation.

Explanation:
Reproduction serves to continue the species which would otherwise extinct due to struggle for survival and natural/accidental death of individuals.

Question 2.

A feature of reproduction that is common to Amoeba, Spirogyra and Yeast are that

(A) they reproduce asexually.
(B) they are all unicellular.
(C) they reproduce only sexually.
(D) they are all multicellular.
Answer:
(A) they reproduce asexually.

Explanation:
All of them reproduce asexually. with single parent and no need of fusion of gametes.

Question 3.

In Spirogyra, asexual reproduction takes place by

(A) breaking up of filaments into smaller bits.
(B) division of a cell into two cells.
(C) division of a cell into many cells.
(D) formation of young cells from older cells.
Answer:
(A) breaking up of filaments into smaller bits.

Explanation:
Fragmentation is a type of asexual reproduction in animals in which parental body is broken down into pieces and each of these pieces develop into an individual animal.

Question 4.

The ability of a cell to divide into several cells during reproduction in Plasmodium is called

(A) budding
(B) reduction division
(C) binary fission
(D) multiple fission EES
Answer:
(D) multiple fission EES

Explanation:
Multiple fission is a repeated division of organism to produce many daughter cells all together.

Question 5.

Factors responsible for the rapid spread of bread mould on slices of bread are

(i) large number of spores.
(ii) availability of moisture and nutrients in bread,
(iii) presence of tubular branched hyphae.
(iv) formation of round shaped sporangia.

(A) (i) and (iii)
(B) (ii) and iv)
(C) (i) and (ii)
(D) (iii) and (iv)
Answer:
(C) (i) and (ii)

Explanation:
Bread mould prefers damp and warm substratum with ample supply of nutrients on which its air-borne spores land and germinate to produce mycelium.

Question 6.

In the list of organisms given below, those that reproduce by the asexual method are

(i) Banana
(ii) Dog
(iii) Yeast
(iv) Amoeba

(A) (ii) and (iv)
(B) (i), (iii) and (iv)
(C) (i) and (iv)
(D) (ii), (iii) and (iv)
Answer:
(B) (i), (iii) and (iv)

Question 7.

Offspring formed by asexual method of reproduction have greater similarity among themselves because

(i) asexual reproduction involves only one parent.
(ii) asexual reproduction does not involve gametes.
(iii) asexual reproduction occurs before sexual reproduction.
(iv) asexual reproduction occurs after sexual reproduction.

(A) (i) and (ii)
(B) (i) and (iii)
(C) (ii) and (iv)
(D) (iii) and (iv)
Answer:
(A) (i) and (ii)

Explanation:
Asexual reproduction does not 1 involve gamete formation and fertilization.

Question 8.

Vegetative propagation refers to formation of new plants from

(A) stem, roots and flowers.
(B) stem, roots and leaves.
(C) stem, flowers and fruits.
(D) stem, leaves and flowers.
Answer:
(B) stem, roots and leaves.

Explanation:
Flowers are the organs of sexual reproduction in plants.

Question 9.

Asexual reproduction takes place through budding in

(A) Amoeba
(B) Yeast
(C) Plasmodium
(D) Leishmania
Answer:
(B) Yeast

Explanation:
Asexual reproduction takes place through budding in yeast.

Question 10.

Which of the following are examples of vegetative reproduction in plants?

(A) Tomato, lady’s finger, onion and cauliflower
(B) Potato, ginger, onion and sugarcane
(C) Cauliflower, onion, potato and tomato
(D) Lady’s finger, onion, ginger and sugarcane
Answer:
(B) Potato, ginger, onion and sugarcane

Explanation:
Potato, ginger, onion, and sugarcane exhibit vegetative reproduction.

Question 11.

In a flower, the parts that produce male and female gametes (germ cells) are

(A) stamen and anther
(B) filament and stigma
(C) anther and ovary
(D) stamen and style
Answer:
(C) anther and ovary

Explanation:
In a flower, pollen grains are formed inside the anther, which produces the male gametes while the ovary bears the female gamete.

Question 12.

Which of the following is the correct sequence of events of sexual reproduction in a flower?

(A) Pollination, fertilisation, seedling, embryo
(B) Seedling, embryo, fertilisation, pollination
(C) Pollination, fertilisation, embryo, seedling
(D) Embryo, seedling, pollination, fertilisation
Answer:
(C) Pollination, fertilisation, embryo, seedling

Explanation:
The correct sequence of events of sexual reproduction in a flower is pollination, fertilization, embryo, seedling. Pollination is the process of transfer of pollens from stamen to stigma after which fertilization takes place, during which germ cells fuse together to form zygote which in turn leads to embryo formation within the ovule. Fertilized ovule becomes seed and seeds germinate to produce seedling.

Question 13.

The correct sequence of reproductive stages seen in flowering plants is

(A) gametes, zygote, embryo, seedling
(B) zygote, gametes, embryo, seedling
(C) seedling, embryo, zygote, gametes
(D) gametes, embryo, zygote, seedling
Answer:
(A) gametes, zygote, embryo, seedling

Explanation:
Gamete formation is followed by pollination and fertilization to produce zygote which in turn leads to embryo formation. Fertilized ovule become seed and seeds germinate to produce seedling.

Question 14.

Which of the following statements are true for flowers?

(i) Flowers are always bisexual.
(ii) They are the sexual reproductive organs.
(iii) They are produced in all groups of plants.
(iv) After fertilisation they give rise to fruits.

(A) (i) and (iv)
(B) (ii) and (iii)
(C) (i) and (iii)
(D) (ii) and (iv)
Answer:
(D) (ii) and (iv)

Explanation:
Flowers are the sexual reproductive organs of a plant and a fertilized flower gives rise to fruit.

Question 15.

A student while observing an embryo of a gram seed listed various parts of the embryo as listed below: Testa, Micropyle, Cotyledon, Tegmen, Plumule, Radicle. On examining the list the teacher commented that only three parts are correct. Select these three correct parts:

(A) Cotyledon, Testa, Plumule
(B) Cotyledon, Plumule, Radicle
(C) Cotyledon, Tegmen, Radicle
(D) Cotyledon, Micropyle, Plumule
Answer:
(B) Cotyledon, Plumule, Radicle

Explanation:
When a plant produces a seed, it has basic parts: plumule (the future shoot), radicle (the future root) and the cotyledons which may be 2 or 1 based on the type of plant being it dicot or monocot, respectively.

Question 16.

Characters that are transmitted from parents to offspring during reproduction show

(A) only similarities with parents
(B) only variations with parents
(C) both similarities and variations with parents
(D) neither similarities nor variations
Answer:
(C) both similarities and variations with parents

Explanation:
Meiosis during gamete formation and fertilization produce variations while DNA replication ensures similarities.

Question 17.

Length of pollen tube depends on the distance between

(A) pollen grain and upper surface of stigma
(B) pollen grain on upper surface of stigma and ovule
(C) pollen grain in anther and upper surface of stigma
(D) upper surface of stigma and lower part of style
Answer:
(B) pollen grain on upper surface of stigma and ovule

Explanation:
Pollen tube carries male gametes to ovule and thus, is long equal to the distance between stigma and ovary.

Question 18.

The number of chromosomes in parents and offsprings of a particular species remains constant due to

(A) doubling of chromosomes after zygote formation
(B) halving of chromosomes during gamete formation
(C) doubling of chromosomes after gamete formation
(D) halving of chromosomes after gamete formation
Answer:
(B) halving of chromosomes during gamete formation

Explanation:
Meiosis reduces the chromosome number to half which is then restored by fertilization.

Question 19.

During adolescence, several changes occur in the human body. Mark one change associated with sexual maturation in boys.

(A) Loss of milk teeth
(B) Increase in height
(C) Cracking of voice
(D) Weight gain
Answer:
(C) Cracking of voice

Explanation:
Cracking of voice is one of the secondary sexual characters of human males observed during adolescence.

Question 20.

In human females, an event that reflects onset of reproductive phase is

(A) growth of body
(B) changes in hair pattern
(C) change in voice
(D) menstruation
Answer:
(D) menstruation

Explanation:
Development of female secondary sexual characters marks onset of puberty and initiation of menstrual cycle reflects onset of reproductive phase.

Question 21.

In human males, the testes lie in the scrotum, because it helps in the

(A) process of mating.
(B) formation of sperm.
(C) easy transfer of gametes.
(D) all of the above.
Answer:
(B) formation of sperm.

Explanation:
Scrotum provides lower temperature needed for sperm formation.

Question 22.

Which among the following is not the function of testes at puberty?

(i) Formation of germ cells
(ii) Secretion of testosterone
(iii) Development of placenta
(iv) Secretion of estrogen

(A) (i) and (ii)
(B) (ii) and (iii)
(C) (iii) and (iv)
(D) (i) and (iv)
Answer:
(C) (iii) and (iv)

Explanation:
Development of placenta and secretion of estrogen are female reproductive functions.

Question 23.

Which of these statement is correct about reproduction ?

(A) It keeps the individual organism alive
(B) It fulfills their energy requirement
(C) It maintains the growth
(D) It continue the species generation after generation
Answer:
(D) It continue the species generation after generation

Explanation:
Reproduction serves to continue the species which would otherwise extinct due to struggle for survival and natural accidental death of individuals.

Question 24.

The correct sequence of organs in the male reproductive system for transport of sperms is

(A) testis → vas deferens → urethra
(B) testis → ureter → urethra
(C) testis → urethra → ureter
(D) testis → vas deferens → ureter
Answer:
(A) testis → vas deferens → urethra

Explanation:
Vas deferens delivers sperms from testes to urethra coming from the urinary bladder.

Question 25.

Which among the following diseases is not sexually transmitted?

(A) Syphilis
(B) Hepatitis
(C) HIV – AIDS
(D) Gonorrhoea
Answer:
(B) Hepatitis

Explanation:
Hepatitis is water borne viral disease.

Question 26.

Which of the following is not a part of the female reproductive system in human beings?

(A) Ovary
(B) Uterus
(C) Vas deferens
(D) Fallopian tube
Answer:
(C) Vas deferens

Explanation:
Vas deferens is not a part of the female reproductive system in human beings.

Assertion and Reason Based MCQs
Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

(A) Both A and R are true and R is the correct explanation of A.
(B) Both A and R are true but R is NOT the correct explanation of A.
(C) A is true but R is false.
(D) A is false and R is true.

Question 1.

Assertion (A): Amoeba reproduces by binary fission.
Reason (R): All unicellular organisms reproduce asexually.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Amoeba is a unicellular organism. It reproduces asexually through binary fission. It is the division of one cell into two similar or identical cells.

Question 2.

Assertion (A): Plants are vegetatively propagated even though they bear seeds.
Reason (R): Potatoes reproduces through tubers, apples by cutting etc.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Vegetative reproduction happens through the use of vegetative parts of the plants, such as leaves, stems, and roots to produce new plants or through growth from specialized vegetative plant parts.

Question 3.

Assertion (A): Characteristics of parental plants can be preserved through asexual reproduction.
Reason (R): Vegetative reproduction involves only mitosis.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Asexual reproduction involves a single individual, which give rise to new individual that are genetically identical to parents. It is because, when organisms reproduce asexually, only mitotic divisions are involved and the chromosome number remains the same.

Question 4.

Assertion (A): Plasmodium reproduces by multiple fission.
Reason (R): Multiple fission is a type of asexual reproduction.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Plasmodium reproduces asexually by multiple fission.

Question 5.

Assertion (A): DNA copying is necessary during reproduction.
Reason (R): DNA copying leads to the transmission of characters from parents to offspring.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
DNA copying is necessary during reproduction because it leads to the transmission of characters from parents to offsprings and brings about variation.

Question 6.

Assertion (A): An embryo is formed from fertilized egg
Reason (R): A monocot embryo comprises embryo¬nal axis with two cotyledons.

Answer:
(C) A is true but R is false.

Explanation:
Zygote, a fertilized egg give rise to an embryo, which has the ability to develop into a complete plant. A typical dicot embryo comprises an embryonal axis with two cotyledons.

Question 7.

Assertion (A): Unisexual flowers have separate male and female flowers whereas a typical monocot embryo comprises an embryonal axis with single cotyledon.
Reason (R): Cucumber, pumpkin and water melon are example of unisexual flowers.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Unisexual flowers have separate male and female flowers. The example includes cucumber, pumpkin and watermelon.

Question 8.

Assertion (A): Double fertilisation is unique to angiosperms.
Reason (R): Triple fusion occurs in asexual repro-duction.

Answer:
(C) A is true but R is false.

Explanation:
Double fertilization is a characteristic feature of flowering plants. In this process, out of the two sperm nuclei, one sperm nucleus fuses with the egg nucleus to form an embryo (process is called syngamy) and another fuses with the secondary nucleus to form an endosperm (process is called triple fusion). Because two kinds of fusion syngamy and triple fusion take place, the process is known as double fertilisation.

Question 9.

Assertion: Fertilization results in formation of zygote.
Reason: Zygote divides several times to form an embryo.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Fertilization is a process which involves fusion of male and female germ cells to form zygote. This zygote divides several times to form an embryo. The ovule develops a thick coat and changes into seed. The ovary grows rapidly and ripens to form the fruit.

Question 10.

Assertion (A): Sexual reproduction increases genetic diversities and plays a role in origin of new species.
Reason (R): Sexual reproduction involves formation of gametes and fusion of gametes.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Sexual reproduction involves two parents that results in the offsprings that are not identical to the parents. It causes variations; which are essential for evolution as well as survival of species under unfavourable conditions.

Question 11.

Assertion (A): In human male, testes are extra-abdominal organs which are present inside scrotum. Reason (R): Scrotum has a relatively lower temperature needed for the production and storage of sperms.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Formation of sperm needs lower temperature than the normal body temperature. Hence, testes lie outside the body cavity in the scrotum.

Question 12.

Assertion (A): At puberty, in boys, voice begins to crack and thick hair grows on face.
Reason (R): At puberty, there is decreased secretion of testosterone in boys.

Answer:
(C) A is true but R is false.

Explanation:
Puberty in boys is regulated by male sex hormone called testosterone, which are secreted by testes. In puberty, secondary sexual characters like growth of hair on face, chest, broadening of shoulders and deepening of voice occurs.

Question 13.

Assertion (A): Surgical methods are most effective methods of contraception.
Reason (R): Surgical method blocks gametes transport and hence prevent fertilisation.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Surgical method like vasectomy in male and tubectomy in female prevent pregnancy. These methods block gamete transport and hence prevent fertilisation. They are very effective but reversibility is very poor.

Case-Based MCQs

Attempt any 4 sub-parts from each question. Each sub-part carries 1 mark.
I. Read the following passage and answer any four questions from Question 1. to Question 5.
The growing size of the human population is a cause of concern for all people. The rate of birth and death in a given population will determine its size. Reproduction is the process by which organisms increase their population. The process of sexual maturation for reproduction is gradual and takes place while general body growth is still going on. Some degree of sexual maturation does not necessarily mean that the mind or body is ready for sexual acts or for having and bringing up children. Various contraceptive devices are being used by human beings to control the size of population.

Question 1.

What are common signs of sexual maturation in boys is:

(A) Broadening of shoulders
(B) Development of mammary glands
(C) Broadening of waist
(D) High pitch of voice
Answer:
(A) Broadening of shoulders

Explanation:
Development of mammary glands or breast, broadening of waist and high pitch of voice are the characters of maturation in female

Question 2.

Common sign of sexual maturation in girls is:

(A) Low pitch voice
(B) Appearance moustache and beard
(C) Development of mammary gland
(D) Broadening of shoulders
Answer:
(C) Development of mammary gland

Explanation:
Development of mammary gland is the character of female maturation while Low pitch voice, appearance of moustache and beard, broadening of shoulders

Question 3.

Which contraceptive method changes the hormonal balance of the body?

(A) Condoms
(B) Diaphragms
(C) Oral pills
(D) Both (a) and (b)
Answer:
(C) Oral pills

Explanation:
Oral pills are responsible to prevent ovulation in the female body by hotmonal change while condoms and diaphragm are only contraceptive barrier that doesn’t bring any hormonal changes.

Question 4.

Write two factors that determine the size of a population.

Answer:
Factors are: Birth rate and death rate.

Question 5.

What should be maintained for a healthy society?

(A) rate of birth & death rate
(B) male & female sex ratio
(C) child sex ratio
(D) None of these
Answer:
(B) male & female sex ratio

II. Study the diagram given below and answer any four questions from Question 1. to Question 5.

Question 1.

Identify the above process.

(A) Binary fission
(B) Budding
(C) Fragmentation
(D) Regeneration
Answer:
(B) Budding

Explanation:
Budding is a type of asexual reproduction wherein a daughter organism is formed from a small projection known as bud.

Question 2.

Which organism uses the above method for reproduction?

(A) Yeast
(B) Amoeba
(C) Spirogyra
(D) Leishmania
Answer:
(A) Yeast

Explanation:
Yeast reproduces asexually by budding.
Question 3.

An organism capable of reproducing by two asexual reproduction methods one similar to the reproduction in yeast and the other similar to the reproduction in Planaria is:

(A) Spirogyra
(B) Hydra
(C) Bryophyllum
(D) Paramecium
Answer:
(B) Hydra

Explanation:
Hydra reproduces asexually by budding (as yeast) and by regeneration (as Planaria).

Question 4.

A Planaria worm is cut horizontally in the middle into two halves P and Q such that the part P contains the whole head of the worm. Another Planaria worm is cut vertically into two halves R and S in such a way that both the cut pieces R and S contain half head each. Which of the cut pieces of the two Planaria worms could regenerate to form the complete respective worms?

(A) Only P
(B) Only R and S
(C) P, Rand S
(D) P, Q, R and S
Answer:
(D) P, Q, R and S

Explanation:
Planaria reproduces asexually by regeneration. It is the ability of a fully differentiated organism to give rise to new individual organisms from its body parts. Small cut or broken parts of the organism’s body grow or regenerate into separate individuals.

Question 5.

Among the following select the statements that are true regarding the sexual reproduction in flowering plants?

(1) Fertilisation is a compulsory event
(2) It always results in the formation of zygote
(3) Offsprings formed are clones
(4) It requires two types of gametes

(A) (1) and (4)
(B) (1), (2) and (3)
(C) (1), (2) and (4)
(D) (2), (3) and (4)
Answer:
(B) (1), (2) and (3)

Explanation:
Sexual reproduction in flowers require two types of gametes. The fusion of gametes results in the formation of the zygote. This process is termed as fertilisation.

III. Study the process depicted in the picture given below and answer any four question from Question 1. to Question 5.

1. Parent cell
2. Nucleus divides
3. Cytoplasm divides
4. Two daughter cells

Question 1.

Which of these organisms divides by the above process?

(A) Amoeba
(B) Spirogyra
(C) Leishmania
(D) Yeast
Answer:
(A) Amoeba

Explanation:
Amoeba reproduces asexually by binary fission. It is the division of one cell into two similar or identical cells. The nucleus first divides amitotically into two, followed by the . division of the cytoplasm. The cell finally splits into two daughter cells.

Question 2.

In multiple fission :

(A) Two daughter cells are produced.
(B) Many daughter cells are formed simultaneously.
(C) Two types of gametes fuse together
(D) None of these
Answer:
(B) Many daughter cells are formed simultaneously.

Explanation:
Binary fission: Two daughter cells are produced. Multiple fission: Many daughter cells are formed simultaneously.

Question 3.

Which of the following statement is correct about the above type of reproduction?

(A) It involves two individuals.
(B) It involves a mature parent cell.
(C) It involves union of two types of gametes.
(D) All of these
Answer:
(B) It involves a mature parent cell.

Explanation:
Asexual reproduction involves a single parent.

Question 4.

Which of these statement is correct about the fission in Leishmanial

(A) Splitting into two cells during division can take place in any plane.
(B) Binary fission occurs in a definite orientation in relation to the whip like structure.
(C) Both of these
(D) None of these
Answer:
(B) Binary fission occurs in a definite orientation in relation to the whip like structure.

Explanation:
In Amoeba, splitting into two cells during division can take place in any plane. In Leishmania, binary fission occurs in a definite orientation in relation to the whip like structure.

Question 5.

Which of these are the characteristics of vegetative reproduction?

(i) Involves two individuals
(ii) Daughter cells are genetically identical to the parent.
(iii) The cell division is only mitotic.

(A) (i) and (ii) only
(B) (i) and (iii) only
(C) (ii) and (iii) only
(D) All of these
Answer:
(C) (ii) and (iii) only

Explanation:
The characteristic features of vegetative reproduction are: cell division take place by mitosis and daughter cells formed are genetically identical to the parent.

IV. Study the given diagram and answer any four questions from Question 1. to Question 5 as given below:

Question 1.

The above diagram depicts:

(A) Spore formation in Rhizopus
(B) Fragmentation in Spirogyra
(C) Binary fission in Amoeba
(D) Spore formation in Yeast
Answer:
(A) Spore formation in Rhizopus

Explanation:
Spore formation takes place in Rhizopus.

Question 2.

‘Blobs’ that develop at the tips of the non- reproductive thread is known as :

(A) Hyphae
(B) Sporangia
(C) Spores
(D) Pollens
Answer:
(B) Sporangia

Explanation:
Rhizopus consists of fine thread like projection called hyphae. It has a knob like structure which is involved in reproduction called sporangia. Each sporangium contains hundreds of black spores which gets dispersed into air to germinate on suitable substratum.

Question 3.

The thread like non-reproductive structures is :

(A) Hyphae
(B) Rhizoids
(C) Sporangium
(D) Sporangiophores
Answer:
(A) Hyphae

Explanation:
Rhizopus consists of fine thread like projection called hyphae.

Question 4.

On maturation sporangia of given organism bursts and releases :

(A) Pollens
(B) Spores
(C) Seeds
(D) None of these
Answer:
(B) Spores

Explanation:
On maturation sporangia of given organism bursts and releases spores. They germinate into new individuals under favourable conditions.

Question 5.

Which of these plants reproduces in the same way as the given process?

(A) Balsam
(B) Fern
(C) Mango
(D) Hibiscus
Answer:
(B) Fern

Explanation:
Fern reproduces by spores.

V.The given diagram represent the structure of a flower. Study the structure and answer any four questions from Question 1. to Question 5.

Question 1.

The labels A, B and C are

(A) Anther, Style and Ovary respectively.
(B) Stamen, Stigma and Ovule respectively.
(C) Anther, Style and Stigma respectively.
(D) Stamen, Fragment and Ovary respectively.
Answer:
(A) Anther, Style and Ovary respectively.

Explanation:
In the given picture, A represents anther, B represents style and C represent ovary.

Question 2.

Which of these is the function of part labelled as C?

(A) Contains ovules which develop into seeds.
(B) Attracts pollinators.
(C) Protect rising buds.
(D) Receive pollens
Answer:
(A) Contains ovules which develop into seeds.

Explanation:
The part labelled as C is Ovary. Ovary contains ovule which develops into seeds while ovary forms the fruit.

Question 3.

When an insect sits on the flower of a plant then some particles from the little stalks in the flowers sticks to its body and when this insect sits on the flower of another plant, the particles get deposited in that flower. What are these particles?

(A) Dust
(B) Pollens
(C) Grains
(D) Seeds
Answer:
(B) Pollens

Explanation:
Pollen is a powdery substance consisting of pollen grains which are male microgametophytes of seed plants, which produce male gametes (sperm cells).

Question 4.

A student decides to study the impact of removing certain flower parts on fruit formation in plant species X. He chooses three separate plants that are growing in the same plot under uniform conditions. The data is given in the table below.

Plants	Part Removed	Impact on formation
1.	Anther	30% less fruit formed than average plants in the plot
2.	Stigma	No fruit formed
3.	Petal	No significant impact

Which of the following can be inferred from the above data?

(A) Anthers and stigmas are crucial in sexual reproduction in species X.
(B) Pollen grains are probably unable to germinate if they land on other parts of the carpel besides the stigma.
(C) Species X is likely to be wind-pollinated.
(D) Species X relies completely on cross pollination.
Answer:
(C) Species X is likely to be wind-pollinated.

Explanation:
The removal of anthers affects fruit formation in plant this implies that species X relies partially on self-pollination. The removal of either anthers or stigmas affects rate of fruit formation significantly. No fruits are observed when the stigmas in plant 2 are removed. This shows that pollen grains are probably unable to germinate if they land on any other part of the carpel besides the stigma. The petals do not seem to play a significant role in facilitating fruit formation. Species-X is therefore likely to be wind-pollinated with reduced petals.

Question 5.

Which of these events does not take place after fertilisation ?

(A) Formation of zygote.
(B) Development of thick coat around ovule.
(C) Ovary ripens to form fruit.
(D) Transfer of pollen from anther to stigma of a flower.
Ans.
(D) Transfer of pollen from anther to stigma of a flower.

Explanation:
Fertilization results in formation of zygote. Zygote divides several times, to form an embryo. The ovule develops a thick coat and is developed into seed. The ovary grows rapidly and ripens to form the fruit.

VI. Study the diagram given below and answer any four questions from Question 1. to Question 5

Question 1.

The part labelled as A in the diagram is:

(A) Dust
(B) Germs
(C) Pollen
(D) Pollinators
Answer:
(C) Pollen

Explanation:
The part labelled as A is pollen pollen grain.

Question 2.

Which of the following statement is incorrect about pollination?

(A) It precedes fertilization.
(B) It follows fertilization.
(C) It brings male and female gametes closer.
(D) It introduces variations in plants.
Answer:
(B) It follows fertilization.

Explanation:
Fertilization which involves fusion of male and female germ cells can only occur only after pollination.

Question 3.

The importance of the part “C” is :

(A) It carries female gametes.
(B) It carries male gametes.
(C) It carries food for the seeds.
(D) None of these
Answer:
(B) It carries male gametes.

Explanation:
It (pollen tube) carries male gamete to reach egg in embryo sac in ovule

Question 4.

What happens to the part marked ‘D’ after fertilization is over?

(A) Converted into seed.
(B) Converted into fruit
(C) Converted into embryo
(D) Converted into flower.
Answer:
(C) Converted into embryo

Explanation:
The part maked ‘D’ is ovule. Flowering plants (angiosperms) create embryos after the fertilization of a haploid ovule by pollen. The DNA from the ovule and pollen combine to form a diploid, single-cell zygote that will develop into an embryo.

Question 5.

Choose the incorrect statements about the reproductive system of a plant?

(A) The male organs are the stamens.
(B) The anthers produce female gametes.
(C) The male gametes are present in the pollen grains.
(D) A male gamete from a pollen grain fertilize a female gamete in an ovule.
Answer:
(B) The anthers produce female gametes.

Explanation:
In a flower, the male reproductive parts are anthers which produce the male gametes.

VII. Study the diagram given below and answer any four questions from Question 1. to Question 5.

Question 1.

The part labelled as A is:

(A) Dust
(B) Germs
(C) Pollen
(D) Pollinators
Answer:
(C) Pollen

Explanation:
The part labelled as A is male germ cells (pollen grain).

Question 2.

The role of part labelled as B is:

(A) Transport of male gametes to the ovary.
(B) Transport of female gametes to the ovary
(C) Contains ovules which develop into seeds.
(D) All of these
Answer:
(A) Transport of male gametes to the ovary.

Explanation:
Style facilitate the transport of the male gametes to the ovary.

Question 3.

How many male gametes are produced by each pollen grain?

(A) One
(B) Two
(C) Three
(D) Four
Answer:
(B) Two

Explanation:
Each pollen grain produces two 1 male gametes.

Question 4.

What happens to the label A which falls on a suitable stigma?

(A) Pollen grain gradually disintegrates.
(B) Pollen grain directly reaches the embryo sac.
(C) Pollen grain starts germinating and forms a pollen tube.
(D) Pollen grain changes into ovules and then to fruit.
Answer:
(C) Pollen grain starts germinating and forms a pollen tube.

Explanation:
The part labelled A is pollen. The pollen grain starts germinating and forms a pollen tube. The pollen tube grows into the style till it reaches the ovule through micropyle. The pollen tube then reaches the embryo sac into which it releases the two male gametes contained in it. The male gamete then fuses with the female gamete in the embryo sac.

Question 5.

In the given diagram showing the carpel of an insect pollinated flower, the most likely reason for the non-germination of pollen grain Z is :X

(A) Pollen grains X and V were brought to the stigma earlier, therefore, their germination inhibited the germination of pollen grain Z.
(B) Pollen grain Z was brought to the flower by wind, while pollen grains X and Y were brought to the flower by insects.
(C) Pollen grain Z lacks protrusions that allow it to adhere properly onto the stigma surface.
(D) Pollen grain Z comes from a flower of an incompatible species.
Answer:
(D) Pollen grain Z comes from a flower of an incompatible species.

Explanation:
Pollen grains can only germinate if the pollen grain and stigma are compatible, i.e., of the same or closely related species. Pollen grains X and Y must have come from a compatible species. Only compatible pollen grains germinate and form pollen tubes

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 8 How do Organisms Reproduce? Read More »

MCQ Questions for Class 10 Science Chapter 6 Life Processes

MCQ Questions / Prasanna

Life Processes Class 10 MCQ Questions With Answers

Question 1.

Which of the following statements about the autotrophs is incorrect?

(A) They synthesise carbohydrates from carbon dioxide and water in the presence of sunlight and chlorophyll.
(B) They store carbohydrates in the form of starch.
(C) They convert carbon dioxide and water into carbohydrates in the absence of sunlight.
(D) They constitute the first trophic level in food chains
Answer:
(C) They convert carbon dioxide and water into carbohydrates in the absence of sunlight.

Explanation:
Autotrophs take in food from the outside world and convert them into stored forms of energy. This material is taken in the form of carbon dioxide and water which is converted into carbohydrates in the presence of sunlight and chlorophyll.

Question 2.

In which of the following groups of organisms, food material is broken down outside the body and absorbed?

(A) Mushroom, green plants, Amoeba
(B) Yeast, mushroom, bread mould
(C) Paramecium, Amoeba, Cuscuta
(D) Cuscuta, lice, tapeworm W
Answer:
(B) Yeast, mushroom, bread mould

Explanation:
These are saprotrophs and digestion in saprotrophs take place before ingestion. They break down and convert complex organic molecules present in dead and decaying matter into simpler substances outside their body.

Question 3.

Which is the correct sequence of parts in human alimentary canal?

(A) Mouth → stomach → small intestine → oesophagus → large intestine
(B) Mouth → oesophagus → stomach → large intestine → small intestine
(C) Mouth → stomach → oesophagus → small intestine → large intestine
(D) Mouth → oesophagus → stomach → small intestine → large intestine
Answer:
(D) Mouth → oesophagus → stomach → small intestine → large intestine

Explanation:
The sequence of organs in human alimentary canal are: Mouth, oesophagus, stomach, small intestine, large intestine and anus.

Question 4.

If salivary amylase is lacking in the saliva, which of the following events in the mouth cavity will be affected?

(A) Proteins breaking down into amino acids
(B) Starch breaking down into sugars
(C) Fats breaking down into fatty acids and glycerol
(D) Absorption of vitamins
Answer:
(B) Starch breaking down into sugars

Explanation:
If salivary amylase is lacking in the saliva, the process of starch digestion will get disturb as salivary amylase helps in digestion of starch.

Question 5.

Select the correct statement.

(A) Heterotrophs do not synthesise their own food.
(B) Heterotrophs utilise solar energy for photosynthesis.
(C) Heterotrophs synthesise their own food.
(D) Heterotrophs are capable of converting carbon dioxide and water into carbohydrates.
Answer:
(A) Heterotrophs do not synthesise their own food.

Explanation:
Heterotrophs are organisms which cannot make their own food from inorganic substances like CO₂ and water as they do not have chlorophyll to trap solar energy. They depend on other organisms for their food. Autotrophs synthesize their own food through photosynthesis by utilizing solar energy, e.g., green plants.

Question 6.

The autotrophic mode of nutrition requires

(A) carbon dioxide and water
(B) chlorophyll
(C) sunlight
(D) all of these
Answer:
(D) all of these

Explanation:
The autotrophic mode of nutrition requires carbon dioxide, water, chlorophyll and sunlight.

Question 7.

The inner lining of stomach is protected by one of the following from hydrochloric acid. Choose the correct one.

(A) Pepsin
(B) Mucus
(C) Salivary amylase
(D) Bile 5
Answer:
(B) Mucus

Explanation:
The stomach has a lining of mucus cells. The mucus is secreted in the gastric juice by the glands present in the stomach wall. It helps to protect the wall of stomach from its own secretions of hydrochloric acid. If mucus is not secreted, HCl will cause the erosion of inner lining of stomach leading to ulcer formation.

Question 8.

A few drops of iodine solution were added to rice water. The solution turned blue-black in colour. This indicates that rice water contains

(A) complex proteins
(B) simple proteins
(C) fats
(D) starch
Answer:
(D) starch

Explanation:
The formation of blue-black colour of rice water confirms the presence of starch. Starch forms a dark blue complex with iodine. When iodine is added it will show no colour change in case of proteins or fats.

Question 9.

The breakdown of pyruvate to give carbon dioxide, water and energy takes place in

(A) cytoplasm
(B) mitochondria
(C) chloroplast
(D) nucleus
Answer:
(B) mitochondria

Explanation:
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in mitochondria.

Question 10.
The correct sequence of anaerobic reactions in yeast is

Answer:

Explanation:
Yeast is an unicellular eukaryote which carries out ethanol fermentation. In the first phase, glucose is converted into pyruvate (glycolysis) in the cytoplasm of the cell. Due to limited oxygen availability, pyruvate remains in cytoplasm where pyruvate decarboxylase and alcohol dehydrogenase enzymes carry out the second phase of anaerobic respiration and produce ethanol and carbon dioxide.

Question 11.

Which of the following statement(s) is (are) correct?

(i) Pyruvate can be converted into ethanol and carbon dioxide by yeast.
(ii) Fermentation takes place in aerobic bacteria.
(iii) Fermentation takes place in mitochondria.
(iv) Fermentation is a form of anaerobic respiration.

(A) (i) and (iii)
(B) (ii) and (iv)
(C) (i) and (iv)
(D) (ii) and (iii)
Answer:
(C) (i) and (iv)

Explanation:
Yeast is a unicellular organism which brings out ethanol fermentation. The first stage is break down of one molecule of glucose into two molecules of pyruvate that occurs in cytoplasm. Because of limited oxygen availability, pyruvate remains in cytoplasm where pyruvate decarboxylase and alcohol dehydrogenase enzymes carry out the second phase of anaerobic respiration and produce ethanol and carbon dioxide.

Question 12.

During deficiency of oxygen in tissues of human beings, pyruvic acid is converted into lactic acid in the

(A) cytoplasm
(B) chloroplast
(C) mitochondria
(D) golgi body
Answer:
(A) cytoplasm

Explanation:
Lactic acid is formed after anaerobic respiration in muscle cells and this happens in cytoplasm.

Question 13.

Which of the following completes the given equation? Glucose + Oxygen (?)

(A) Only carbon dioxide + water + energy
(B) Only carbon dioxide + water
(C) Only carbon dioxide
(D) Only water + energy
Answer:
(A) Only carbon dioxide + water + energy

Explanation:
The given equation represents aerobic respiration. Glucose + oxygen -»carbon dioxide + water+ energy

Question 14.

Which of the following take place after we exercise?

(A) Out body needs more oxygen.
(B) Our body needs to replace the energy used.
(C) Our body needs to get rid of excess carbon dioxide.
(D) All of these 53
Answer:
(D) All of these 53

Explanation:
Our body needs more energy when we do exercise. We get energy by the oxidation of food. Due to exercise the body is able to get rid of excess carbon dioxide.

Question 15.

Which of these statements is correct about alveoli?

(A) They form a very large surface area.
(B) They have a very thin wall.
(C) They are covered with blood capillaries.
(D) All of these
Answer:
(D) All of these

Explanation:
Alveoli have a large surface area with very thin walls which is richly supplied with blood vessels and are always moist.

Question 16.

As air passes through the nasal cavity, it is

(A) Filtered in the nostrils
(B) Moistened by mucus
(C) Warmed to the body temperature
(D) Al of these
Answer:
(D) Al of these

Explanation:
Before air is breathed into the lungs, it is filtered in the nostrils, moistened by mucus and gets warmer equal to the body temperature.

Question 17.

What prevents back flow of blood inside the heart during contraction?

(A) Valves in heart
(B) Thick muscular walls of ventricles
(C) Thin walls of atria
(D) Al of the above
Answer:
(A) Valves in heart

Explanation:
Valves ensure that blood does not flow backwards when the atria or ventricles contract. Semilunar valves, the valves present between ventricles and their attached vessels, serve to prevent the backflow of blood to ventricles from their respective attached vessels. Likewise, atrioventricular (AV) valve between atrium and ventricle directs the flow of blood and prevents any backflow into atria.

Question 18.

Single circulation, i.e., blood flows through the heart only once during one cycle of passage through the body, is exhibited by

(A) Labeo, Chameleon, Salamander
(B) Hippocampus, Exocoetus, Anabas
(C) Hyla, Ram, Draco
(D) Whale, Dolphin, Turtle
Answer:
(B) Hippocampus, Exocoetus, Anabas

Explanation:
Hippocampus, Exocoetus, Ambas belong to class pisces. Fishes have two chambered heart and exhibit single circulation while three chambered heart of amphibians and reptiles and four chambered heart of birds and mammals exhibit double circulation.

Question 19.

The blood leaving the tissues becomes richer in

(A) carbon dioxide
(B) water
(C) haemoglobin
(D) oxygen 5
Answer:
(A) carbon dioxide

Explanation:
The anterior vena cava collects deoxygenated blood from the head, chest, and arms and enters the right atrium while the inferior vena cava collects blood from the lower body regions. Both venae cavae pass the deoxygenated blood to the right atrium. Therefore, blood from tissues is rich in carbon dioxide.

Question 20.

The xylem in plants are responsible for

(A) transport of water
(B) transport of food
(C) transport of amino acids
(D) transport of oxygen
Answer:
(A) transport of water

Explanation:
In a plant, the xylem is responsible for transport of water.

Question 21.

Which of the following statement(s) is (are) true about heart?

(i) Left atrium receives oxygenated blood from different parts of body while right atrium receives deoxygenated blood from lungs.
(ii) Left ventricle pumps oxygenated blood to different body parts while right ventricle pumps deoxygenated blood to lungs.
(iii) Left atrium transfers oxygenated blood to right ventricle which sends it to different body parts,
(iv) Right atrium receives deoxygenated blood from different parts of the body while left ventricle pumps oxygenated blood to different parts of the body

(A) (i)
(B) (ii)
(C) (ii) and (iv)
(D) (i) and (iii)
Answer:
(C) (ii) and (iv)

Explanation:
Blood from right atrium enters right ventricle and pulmonary arteries carry deoxygenated blood from right ventricle to lungs for oxygenation.

Question 22.

In which of the following vertebrate group/ groups, heart does not pump oxygenated blood to different parts of the body?

(A) Pisces and amphibians
(B) Amphibians and reptiles
(C)Amphibians only
(D) Pisces only
Answer:
(D) Pisces only

Explanation:
In fishes, heart sends the blood to gills from where blood is circulated to different orgAnswer:

Question 23.

Choose the correct statement that describes arteries.

(A) They have thick elastic walls, blood flows under high pressure; collect blood from different organs and bring it back to the heart.
(B) They have thin walls with valves inside, blood flows under low pressure and carry blood away from the heart to various organs of the body.
(C) They have thick elastic walls, blood flows under low pressure; carry blood from the heart to various organs of the body.
(D) They have thick elastic walls without valves inside, blood flows under high pressure and carry blood away from the heart to different parts of the body.
Answer:
(D) They have thick elastic walls without valves inside, blood flows under high pressure and carry blood away from the heart to different parts of the body.

Explanation:
Arteries are the valveless blood vessels which serve to transport the blood away from the heart to various body parts. The thick strong elastic walls of arteries withstand the high pressure of blood coming from heart.

Question 24.

Which of these statements is correct about the function of blood?

(A) It helps in transportation of respiratory gases.
(B) It regulates body temperature.
(C) It helps in transportation of waste products.
(D) All the above
Answer:
(D) All the above

Explanation:
Blood has many different functions, like transporting oxygen and nutrients to the lungs and tissues, regulating body temperature, forming blood clots to prevent excess blood loss, and carrying cells and antibodies that fight infection.

Question 25.

The filtration units of kidneys are called

(A) ureter
(B) urethra
(C) neurons
(D) nephrons
Answer:
(D) nephrons

Explanation:
Nephrons are the structural and functional unit of kidney that serve in filtration, reabsorption and secretion. Ureters are small muscular tubes that extend from the kidney and carry urine into the urinary bladder. The urethra is a canal that carries urine from bladder and expels it out of body. Neurons are structural and functional unit of nervous system.

Question 26.

The kidneys in human beings are a part of the sys-tem for

(A) nutrition
(B) respiration
(C) excretion
(D) transportation.
Answer:
(C) excretion

Explanation:
In human beings, the kidneys are a part of the system for excretion.

Question 27.

Match the words of Column (A) with that of Column (B)

Column (A)	Column (B)
(A) Phloem	(i) Excretion
(B) Nephron	(ii) Translocation of food
(C) Veins	(iii) Clotting of blood
(D) Platelet	(iv) Deoxygenated blood

(A) A – (ii), B – (i), C – (iv), D – (iii)
(B) A – (iii), B – (ii), C – (i), D – (iv)
(C) A – (iv), B – (iii), C – (ii), D – (i)
(D) A – (i), B – (iv), C – (iii), D – (iv)
Answer:
(A) A – (ii), B – (i), C – (iv), D – (iii)
Explanation:
S. No. Column
(A) Column
(B) Explanation

S. No	Column (A)	Column (B)	Expianation
A	Phloem	(ii)	Phloem helps in translocation of food.
B	Nephron	(i)	Nephron helps in excretion.
C	Veins	(iv)	Veins carry deoxy-genated blood.
D	Platelets	(iii)	Platelets helps in clotting of blood.

Question 28.

Which of the following is the structural and functional unit of the excretory system?

(A) Neuron
(B) Nephron
(C) Alveolus
(D) Both (A) and (B)
Answer:
(B) Nephron

Explanation:
Nephron is the structural and functional unit of excretory system.

Question 29.

Choose the correct path of urine in our body :

(A) kidney → ureter → urethra → urinary bladder
(B) kidney → urinary bladder → urethra → ureter
(C) kidney → ureters —> urinary bladder →urethra
(D) urinary bladder → kidney → ureter → urethra
Answer:
(C) kidney → ureters —> urinary bladder →urethra

Explanation:
Kidneys are the paired organ where urine formation takes place. Small muscular tube, called as ureter, extend from kidneys and carry blood to urinary bladder. The urethra is a small tube that extends from the urinary bladder to an external opening.

Question 30.

Which of the following substances are removed from blood in the kidneys?

(A) Water
(B) Urea
(C) Sodium
(D) Ammonia
Answer:
(B) Urea

Explanation:
Urea is removed by the blood in kidneys by filtration.

Question 31.

Each nephron has a cup shaped upper end called…………… . which contains a………. .

(A) Bowman’s capsule, Ampulla
(B) Capillaries, Bowman’s capsule
(C) Ampulla, Glomerulus
(D) Bowman’s capsule, Glomerulus
Answer:
(D) Bowman’s capsule, Glomerulus

Explanation:
The upper cup shaped end of a nephron is called Bowman’s capsule. It contains glomerulus which is a group of blood capillaries.

Question 32.

Which of the following is used artificially to remove nitrogenous waste products from the blood?

(A) Ventilator
(B) Transfusion
(C) Hemodialysis
(D) Angiogram
Answer:
(C) Hemodialysis

Explanation:
Hemodialysis is used to remove nitrogenous waste products from the blood.

Assertion and Reason Based MCQs

Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:
(A) Both A and R are true and R is the correct explanation of A.
(B) Both A and R are true but R is NOT the correct explanation of A.
(C) A is true but R is false.
(D) A is false and R is true.

Question 1.

Assertion (A): HCl converts pepsinogen into active enzyme pepsin.
Reason (R): Pepsin converts protein into proteoses and peptones.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
HCl creates an acidic medium, which facilitates activation of pepsinogen into pepsin. The active enzyme pepsin converts proteins into proteoses and peptones.

Question 2.

Assertion (A): Digestion breaks large complex molecules to simple smaller molecules which can be easily absorbed.
Reason (R): Digestion is necessary for the absorption of all molecules.

Answer:
(C) A is true but R is false.

Explanation:
Digestion breaks large complex organic molecules to simple smaller ones which can be easily absorbed. However, certain molecules such as glucose, vitamin C etc, do not need any digestion before their absorption.

Question 3.

Assertion (A): Muscles of stomach wall possess thick layers of muscle fibers.
Reason (R): These muscles help in mixing the food with the enzymes present in the alimentary canal.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
The lining of alimentary canal has muscles that contract rhythmically in order to push the food forward. This is known as peristaltic movement.

Question 4.

Assertion (A): Lipases help in emulsification of fats.
Reason (R): Lipases hydrolyses fats and oils.

Answer:
(D) A is false and R is true.

Explanation:
Bile helps in emulsification of fats whereas lipases are the enzymes which hydrolyze fats and oils.

Question 5.

Assertion (A): Photosynthesis is an anabolic process.
Reason (R): The process of photosynthesis occurs in chlorophyll.

Answer:
(C) A is true but R is false.

Explanation:
Photosynthesis is an anabolic process as it takes C02 and H20 and then assembles them into glucose. The process of photosynthesis occurs in chloroplast.

Question 6.

Assertion (A): Energy is used during the process of respiration.
Reason (R): Respiration stores energy in the form of ATP.

Answer:
(D) A is false and R is true.

Explanation:
Respiration involves the oxidation of glucose inside the mitochondria to produce energy, which is stored in the high energy bonds of ATP molecules as biologically useful energy.

Question 7.

Assertion (A): Humans are not truly aerobic.
Reason (R): They produce lactic acid anaerobically.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Humans are aerobically respiring animals, but sometimes anaerobic respiration takes place in certain tissues like skeletal muscles, which do not get immediately as much oxygen as it requires. Therefore, the muscles respire anaerobically and produce lactic acid from glucose.

Question 8.

Assertion (A): In humans, there is a complex respiratory system.
Reason (R): Human skin is impermeable to gases.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Humans need more oxygen to maintain their high metabolic rates. Thus, a complex respiratory system has evolved so as to meet this need.

Question 9.

Assertion (A): Alveoli contain an extensive network of blood vessels.
Reason (R): Alveoli is the site where exchange of gases occurs.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
The alveoli of lungs are richly supplied with blood and are the sites where exchange of gases (O₂ and CO₂) occurs between blood and atmosphere.

Question 10.

Assertion (A): The muscular walls of ventricles are thicker than auricles.
Reason (R): This helps in preventing the back flow of blood.

Answer:
(C) A is true but R is false.

Explanation:
Since ventricles have to pump blood into various organs, they have thicker muscular walls than atria do. Valves prevent back flow of blood.

Question 11.

Assertion (A): In human heart, there is no mixing of oxygenated and deoxygenated blood.
Reason (R): Valves are present in the heart which allows the movement of blood in one direction only.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
There is no mixing of oxygenated and deoxygenated blood due to presence of inter-auricular and inter – ventricular septum. On the other hand, valves are present in the heart which allows the movement of blood in one direction only.

Question 12.

Assertion (A): Valves are present in the arteries.
Reason (R): Arteries carry oxygenated blood from heart to different body parts except pulmonary artery.

Answer:
(D) A is false and R is true.

Explanation:
Valves are absent in arteries, I whereas it is present in veins, which prevent back flow of blood.

Question 13.

Assertion (A): Plants have low energy needs.
Reason (R): Plant bodies have large proportion of dead cells.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Because plants have a large proportion of dead cells in many tissues. So, their energy needs are low and they can afford to have slow transport system.

Question 14.

Assertion (A): Human body produces highly toxic substances, which if not eliminated may cause the death.
Reason (R): Excretory substance removes nitrog-enous waste from the body.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
The biological process which involves the removal of harmful metabolic wastes from the body is called excretion. If these harmful wastes are not removed from the body, then it may cause the death of the organism.

Question 15.

Assertion (A): Excretory unit of kidneys are nephrons.
Reason (R): It has no role in secretion of urine.

Answer:
(C) A is true but R is false.

Explanation:
Nephrons are the basic filtration unit of kidneys. They carry out filtration, selective reabsorption and tubular secretion to from urine in kidneys, which is then passed out through the urethra, via the ureters and urinary bladder.

Question 15.

Assertion (A): Haemodialysis can save the life of patients with kidney failure.
Reason (R): Waste products like urea can be removed from the blood by haemodialysis.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
In case of kidney failure, haemodialysis is the process of purifying blood (or removing waste products like urea) by an artificial kidney. This can save the life of the patient.

Question 16.

Assertion (A): In humans, major amount of water is absorbed by the tubular part of nephron.
Reason (R): Absorption of water depends on the dissolved waste to be excreted from the body.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Major amount of water is selectively re-absorbed by the tubular part of nephron in humAnswer: It depends on the amount of excess water present in the body and dissolved waste to be excreted from the body.

Case-Based MCQs

Attempt any 4 sub-parts from each question. Each sub-part carries 1 mark.

I. Read the given passage and answer any of the four questions from Question l. to Question 5.
Sanjana is suffering from a frequent stomach pain and vomiting. She went to the Doctor. The doctor asked her to go for an ultrasound. In the report, a stone was found in her gall bladder. Doctor asked her to remove the gall bladder by operation. But she was reluctant to go for the operation.

Question 1.

The role played by gall bladder in human body is

(A) To store bile
(B) To secrete bile
(C) To emulsify fats
(D) To digest fats
Answer:
(A) To store bile

Explanation:
Gall bladder stores bile.

Question 2.

Removal of gall bladder

(A) affects the person’s health
(B) Has no effect on the person’s health
(C) Effects the secretion of bile
(D) Effects the digestion of proteins
Answer:
(B) Has no effect on the person’s health

Explanation:
No, the removal of gall bladder will not affect person’s health.

Question 3.

Which of the following statement is correct about bile?

(A) It helps in emulsification of fat.
(B) It helps in digestion of carbohydrates
(C) It helps in absorption of digested food.
(D) It helps in egestion of undigested food.
Answer:
(A) It helps in emulsification of fat.

Explanation:
Bile helps in emulsification of fat.

Question 4.

Which part of alimentary canal receives bile from the liver?

(A) Stomach
(B) Small intestine
(C) Large intestine
(D) Oesophagus
Answer:
(B) Small intestine

Explanation:
Bile is dark green or a yellowish brown fluid which is produced by the liver and comes to the small intestine through hepato-pancreatic duct.

Question 5.

What is the function of bile salt in the intestine?

(A) Activator of lipase
(B) Emulsifier
(C) Co factor of cholesteryl esterase
(D) Inhibitor of lipid absorption
Answer:
(B) Emulsifier

Explanation:
Bile contains bile salts that help in proper digestion of fats by breaking down large fat globules into smaller ones, so that enzyme can easily act on it and digest them. This process is known as emulsification of fats.

II. The given diagram is of human digestive human. Study the diagram and answer any of the four questions from Question 1. to Question 5.

Question 1.

Which of these correctly represent the labels B, C, D and E?

(A) B- Oesophagus, C- Liver, D- Stomach, E- pancreas
(B) B- Pancreas, C- Oesophagus, D- Liver, E- Stomach
(C) B- Stomach, C- Pancreas, D- Oesophagus, E- Liver
(D) B- Liver, C- Stomach, D- Pancreas, E- Oesophagus
Answer:
(A) B- Oesophagus, C- Liver, D- Stomach, E- pancreas

Explanation:
In the given picture of human digestive system, B is Oesophagus, C is Liver,D is Stomach, and E is pancreas.

Question 2.

The secretion that is released by label C is:

(A) Bile
(B) Pepsin
(C) Saliva
(D) Gastric juice
Answer:
(A) Bile

Explanation:
Label C represents liver. Liver secretes bile, which is stored in gall bladder.

Question 3.

Name the digestive juice that lacks enzyme but helps in digestion.

(A) Bile juice
(B) Pancreatic juice
(C) Ptyalin
(D) Pepsin
Answer:
(A) Bile juice

Explanation:
Bile juice doesn’t contain any enzyme. It helps in digestion of fats.

Question 4.

The digestion of food starts in

(A) A
(B) D
(C) E
(D) F
Answer:
(A) A

Explanation:
Label A represents mouth. The digestion of food starts in mouth.

Question 5.

In case of diarrhoea, which major process does not takes place normally in region F?

(A) Absorption of food
(B) Absorption of water
(C) Secretion of hormones
(D) Removal of waste material
Answer:
(B) Absorption of water

Explanation:
Absorption of water is not occurring normally in region F (Large I intestine).

III. Study the given flow chart and answer any of the four questions from Question l. to Question 5.
CO₂+ H₂OCO₂+ C₂H₅OH +energy + energy

Question 1.

Identify X, Y and Z.

(A) X-Glycolysis, Y-Anaerobic, Z-Aerobic
(B) X -Krebs’s cycle, Y-Aerobic, Z-Anaerobic
(C) X-Glycolysis, Y-Aerobic, Z-Anaerobic
(D) X-Glycolysis, Y-Aerobic, Z-Krebs’s cycle
Answer:
(C) X-Glycolysis, Y-Aerobic, Z-Anaerobic

Explanation:
The label X represents the process of Glycolysis, Y – Aerobic respiration, and Z – Anaerobic respiration.

Question 2.

The process X occurs in……….. and Y occurs in………. part of cell.

(A) Mitochondria and cytoplasm respectively
(B) Cytoplasm and mitochondria respectively
(C) Both takes place in cytoplasm
(D) Both takes place in mitochondria
Answer:
(B) Cytoplasm and mitochondria respectively

Explanation:
The breakdown of glucose (a six- carbon molecule) into a three-carbon molecule called pyruvate takes place in the cytoplasm whereas the process of aerobic respiration takes place in mitochondria.

Question 3.

In which of these organisms the process Z takes place?

(A) Bacteria
(B) Humans
(C) Yeast
(D) Spirogyra
Answer:
(C) Yeast

Explanation:
The Z (anaerobic respiration) takes place in yeast. Since the process takes place in the absence of air, it is called anaerobic respiration.

Question 4.

In which part of human body do the process Z takes place?

(A) In muscle cells
(B) In kidneys
(C) In liver cells
(D) In leydig’s cell
Answer:
(A) In muscle cells

Explanation:
In human body, Z (anaerobic respiration) takes place in muscle cells.

Question 5.

Where does aerobic respiration occur in a cell ?

(A) Mitochondria
(B) Cytoplasm
(C) Nucleus
(D) Plastid
Answer:
(A) Mitochondria

Explanation:
Aerobic respiration occurs in mitochondria. Since the process takes place in presence of air (oxygen), it is called aerobic respiration.

IV. Study the diagram of human respiratory system and answer any of the four questions Question 1. to Question 5.

Question 1.

The balloon like structures present in ‘S’ is:

(A) Nephron
(B) Alveoli
(C) Bronchi
(D) Bronchiole
Answer:
(C) Bronchi

Explanation:
The balloon like structure are alveoli. Alveoli are air sacs at the end of bronchioles. They allow oxygen and carbon dioxide to move between the lungs and the blood-stream.

Question 2.

Which of these organ is surrounded by cartilaginous rings?

(A) P
(B) Q
(C) R
(D) S
Answer:
(C) R

Explanation:
R (Trachea) is supported by rings I of cartilage.

Question 3.

Which of these statements is incorrect regarding human lungs?

(A)It is the secondary organ for respiration.
(B) It is located on the two sides of heart.
(C) The membrane that encloses lungs is pleural membrane.
(D) The alveolar epithelium of lungs is non-ciliated epithelium.
Answer:
(A)It is the secondary organ for respiration.

Explanation:
Lungs are the primary breathing organ. It is the main respiratory surface available for the exchange of gases (O₂ CO₂).

Question 4.

Trachea is divided into two smaller tubes called………… .

(A) Bronchi
(B) Bronchioles
(C) Larynx
(D) Alveoli
Answer:
(A) Bronchi

Explanation:
Pharynx splits into trachea and oesophagus. It connects the larynx to the bronchi of the lungs. It provides air flow to and from the lungs for respiration.

Question 5.

Which of these is the function of balloon like structure present in lungs?

(A) Exchange of gases
(B) Absorption of nutrients
(C) Transport of food
(D) Removal of waste materials
Answer:
(A) Exchange of gases

Explanation:
The balloon like structure called alveoli allow oxygen and carbon dioxide to move between the lungs and the blood-stream.

V. The given diagram represents the structure of a human excretory system. Study the diagram and answer any of the four questions from Question 1. to Question 5.

Question 1.

Identify the part in excretion.

(A) Kidney
(B) Ureter
(C) Urethra
(D) Nephron
Answer:
(B) Ureter

Explanation:
Part is ureter. It transports urine from kidney to urinary bladder.

Question 2.

Which of these is the structural and functional unit of part 2?

(A) Alveoli
(B) Nephron
(C) Neuron
(D) None of these
Answer:
(B) Nephron

Explanation:
Nephrons are the structural and functional filtration unit of kidney that serve in filtration, reabsorption and secretion.

Question 3.

How can we purify the blood by artificial methods?

(A) Filtration
(B) Dialysis
(C) Reabsorption
(D) All of these
Answer:
(B) Dialysis

Explanation:
Urea is the main waste present in the urine.

Question 4.

The main waste present in the urine is:

(A) Glucose
(B) Urea
(C) Blood
(D) Protein
Answer:
(B) Urea

Explanation:
Dialysis is a procedure to remove waste products and excess fluid from the blood when the kidneys stop working properly. It often involves diverting blood to a machine to be cleaned.

Question 5.

Choose the correct path of urine in our body:

(A) kidney →tureter → urethra → urinary bladder
(B) kidney → urinary bladder → urethra → ureter
(C) kidney → ureters → urinary bladder → urethra
(D) urinary bladder → kidney → ureter → urethra
Answer:
(C) kidney → ureters → urinary bladder → urethra

Explanation:
Kidneys are the paired organs where urine formation takes place. Small muscular tube, called as ureter, extend from kidneys and carries urine to urinary bladder. The urethra is a small tube that extends from the urinary bladder to an external opening.

VI. Read the given passage and answer any of the four questions from Question l. to Question 5.

Oxygen-rich blood from the lungs comes to the thin-walled upper chamber of the heart on the left. The left upper chamber (A) then relaxes. It then contracts and the blood is allowed to enter the next chamber (B), as it expands. When the muscular left lower chamber of heart contracts the blood is pumped out to the body via aorta.

Deoxygenated blood reaches from the body to the upper chamber on the right side of heart (C) and it expands. As this part contracts, the corresponding lower chamber (D) dilates. This transfers the blood to right ventricle, which in turn pumps it to the lungs for oxygenated.

Question 1.

Which of these correctly represents the label A, B, C and D in the above passage?

(A) A- Left atrium, B- Left Ventricle, C- Right atrium, D- Right ventricle
(B) A- Right ventricle, B- Left atrium, C- Left Ventricle, D- Right atrium
(C) A- Right atrium, B- Right ventricle, C- Left atrium, D- Left ventricle
(D) A- Left ventricle, B- Right atrium, C- Right ventricle, D- Left atrium
Answer:
(A) A- Left atrium, B- Left Ventricle, C- Right atrium, D- Right ventricle

Explanation:
A is Left atrium, B is Left Ventricle, C is Right atrium, and D is Right ventricle.

Question 2.

Which chambers of human heart contain oxygenated blood?

(A) A and B
(B) A and C
(C) C and B
(D) C and D
Answer:
(A) A and B

Explanation:
A (Left atrium) and B (Left ventricle) contain oxygenated blood from lungs.

Question 3.

What is the correct route of blood in a human?

(A) A → B → Lungs → C → D
(B) A → B → D → C → Lungs
(C) C → D → B→ A → Lungs
(D) C → D → Lung → A → B
Answer:
(D) C → D → Lung → A → B

Explanation:
The correct route of blood in a human is : C (Right atrium)→ D (Right ventricle) →Lungs → A (Left atrium) → B (Left ventricle.

Question 4.

What prevents backflow of blood inside the heart during contraction?

(A) Valves in heart
(B) Thick muscular walls of ventricles
(C) Thin walls of atria
(D) All of the above
Answer:
(A) Valves in heart

Explanation:
Valves prevent the back flow of blood inside the heart during contraction of heart chambers (atria or ventricles).

Question 5.

Assertion (A): Human heart does not allow mixing of oxygen rich blood with carbon dioxide rich blood.
Reason (R): Human heart has different chambers.

(A) Both A and R are true and R is correct explanation of the assertion.
(B) Both A and R are true but R is not the correct explanation of the assertion.
(C) A is true but R is false.
(D) A is false but R is true.
Answer:
(C) A is true but R is false.

Explanation:
Human heart is four chambered. It is composed of four chambers : right atrium, right ventricle, left ventricle and left atrium. The chambers are separated by a muscular wall that prevents the mixing of the blood rich in oxygen with the blood rich in carbon dioxide.

VII. Read the passage and answer any of the four questions from Question l. to Question 5.
Some experiments were carried out using Croton sp. plants to understand the process of photosynthesis. It was observed that the leaves of the plant exposed to light for longer duration accumulated more starch. However, due to presence of pre-formed starch in the leaves, it was difficult to find the net productivity on a fixed exposure to light source. Therefore, it was necessary to obtain starch free leaves in the plant before starting the experiment.

Question 1.

Which of the following would help obtain starch free leaves in the plant?

(A) Expose the leaves to blue light for 48 hours before starting the experiment.
(B) Keep the plant in dark for about 48 hours before starting the experiment.
(C) Remove starch from the leaves by exosmosis, 48 hours before starting the experiment.
(D) Keep the leaves to red light for 48 hours before starting the experiment.
Answer:
(B) Keep the plant in dark for about 48 hours before starting the experiment.

Explanation:
The starch free leaves can be j obtained by keeping the plant in dark, so that 1 already present starch is utilized in 48 hrs.

Question 2.

After a period of illumination, the leaves were boiled in alcohol to make them colourless. Which of the following could be used to test the end product stored in the leaves?

(A) Cobalt chloride paper
(B) Litmus paper
(C) Iodine solution
(D) Copper sulphate solution
Answer:
(C) Iodine solution

Explanation:
Starch presence can be tested by adding iodine solution which gives bluish black colour of starch iodine mixture.

Question 3.

Some of the starch free leaves were coated with wax on both the surfaces. The plant was maintained under normal environmental conditions. At the end of the experiment, the wax coated leaves are likely to show .

(A) Accumulation of more water.
(B) Wilting of the wax coated leaves.
(C) Increase in sucrose accumulation.
(D) Decrease in number of chloroplasts
Answer:
(B) Wilting of the wax coated leaves.

Explanation:
Wilting occurs due to wax blocks the transpiration so water transportation inhibits.

Question 4.

During the morning hours, using a fine blade, an incision was made to the leaves such that the phloem tissue was cut open. Analysis of the liquid oozing out was found to contain high amount of:

(A) Xylose
(B) Ribose
(C) Sucrose
(D) Galactose
Answer:
(C) Sucrose

Explanation:
The transport of glucose, occurs in the form of sucrose, in phloem therefore, when cell sap oozes out, liquid contains sucrose.

Question 5.

The equation given below represents photosynthesis. Identify P and Question

(A) P – Carbon dioxide, Q – Oxygen
(B) P – Oxygen, Q – Oxygen
(C) P – Carbon dioxide, Q – Carbon dioxide
(D) P – Oxygen, Q – Carbon dioxide
Answer:
(A) P – Carbon dioxide, Q – Oxygen

Explanation:
The process by which autotrophs take in CO₂and H₂O and convert these into carbohydrates in the presence of chlorophyll, and sunlight is called photosynthesis.
Equation for photosynthesis is :

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 6 Life Processes Read More »

MCQ Questions for Class 10 Science Chapter 5 Periodic Classification of Elements

MCQ Questions / Prasanna

Periodic Classification of Elements Class 10 MCQ Questions With Answers

Question 1.

The positions of four elements A, B, C and D in the modern periodic table are shown below. Which element is most likely to form an acidic oxide?

(A) A
(B) B
(C) C
(D) D
Answer:
(C) C

Explanation:
Element C to form an acidic oxide because it lies in non-metal category.

Question 2.

Elements P, Q, R and S have atomic numbers 11,15, 17 and 18 respectively. Which of them are reactive non-metals?

(A) P and Q
(B) P and R
(C) Q and R
(D) R and S
Answer:
(C) Q and R

Explanation:
Element Q and R are reactive non-metals because they have great tendency to accept the electrons to occupy the stable state configuration.

Question 3.

Consider the following statements about an element ‘X’ with number of protons 13.

(A) It forms amphoteric oxide.
(B) Its valency is three.
(C) The formula of its chloride isHCl.
(D) The correct statements(s) is/are:

(A) only (A)
(B) only (B)
(C) (A) and (C)
(D) (A), (B) and (C)
Answer:
Option (A) and (B) is correct.

Question 4.

Upto which element, the Law of Octaves was found to be applicable ?

(A) Oxygen
(B) Calcium
(C) Cobalt
(D) Potassium
Answer:
(B) Calcium

Explanation:
It was found that the Law of Octaves was applicable only upto calcium, as after calcium every eighth element did not possess properties similar to that of the first.

Question 5.

According to Mendeleev’s Periodic Law, the elements were arranged in the periodic table in the order of

(A) increasing atomic number
(B) decreasing atomic number
(C) increasing atomic masses
(D) decreasing atomic masses R
Answer:
(C) increasing atomic masses

Explanation:
Mendeleev arranged the known elements according to increasing order of their atomic masses because according to him, fundamental property of an element was atomic mass.

Question 6.

In Mendeleev’s periodic table, gaps were left for the elements to be discovered later. Which of the following elements found a place in the periodic table later ?

(A) Germanium
(B) Chlorine
(C) Oxygen
(D) Silicon
Answer:
(A) Germanium

Explanation:
Many gaps for the undiscovered elements were left in the periodic table by Mendeleev. For instance, the elements scandium (Sc), gallium (Ga), and germanium (Ge) were not known at Mendeleev’s time, but he had predicted their existence in advance of their discovery.

Question 7.

What type of oxide would Eka- aluminium form?

(A) EO₃
(B) E₂O₂
(C) E₂O₃
(D) EO
Answer:
(C) E₂O₃

Explanation:
Since, Aluminium forms its oxide as Al(C) E₂O₃O(C) E₂O₃. Hence, Formula of oxide is E₂O₃.

Question 8.

Which of these does not represent Dobereiner’s triad?

(A) Li, Na, K
(B) Cl, Br, I
(C) Be, Mg, Ca
(D) N P As
Answer:
(D) N P As
Explanation:
N, P and As will not represent Dobereiner’s triad. It is because; the average of atomic masses of Nitrogen and Arsenic is not equal to atomic mass of phosphorus.

Question 9.

An element ‘X’ is forming an acidic oxide. Its position in modern periodic table will be:

(A) Group 1 and Period 3
(B) Group 2 and Period 3
(C) Group 13 and Period 3
(D) Group 16 and Period 3
Answer:
Option (D) is correct.

Explanation:
Group 16 and Period 3. Non-metals form acidic oxides.

Question 10.

Where would you locate the element with electronic configuration 2, 8 in the Modern Periodic Table?

(A) Group 8
(B) Group 2
(C) Group 18
(D) Group 10
Answer:
(C) Group 18

Explanation:
Element with electronic configuration 2, 8 has octet configuration, so must be placed in group 18.

Question 11.

Which of the following is the outermost shell for elements of period 2?

(A) K shell
(B) L shell
(C) M shell
(D) N shell
Answer:
(B) L shell

Explanation:
The elements of 2nd period contain two shells, K and L shell.

Question 12.

Arrange the following elements in the order of their decreasing metallic character: Na, Si, Cl, Mg, Al.

(A) Cl > Si >A1 > Mg >Na
(B) Na >Mg >A1 >Si > Cl
(C) Na > Al > Mg > Cl > Si
(D) Al > Na> Si > Ca> Mg
Answer:
(B) Na >Mg >A1 >Si > Cl

Explanation:
As we move from left to right in periodic table, metallic characters decreases and non-metallic characters increases.

Question 13.

Which of the following elements will form an acidic oxide?

(A) An element with atomic number 7
(B) An element with atomic number 3
(C) An element with atomic number 12
(D) An element with atomic number 19
Answer:
(A) An element with atomic number 7

Explanation:
Formation of acidic oxides is a characteristic of non-metals. Here, element with atomic number 7 is a non-metal that is nitrogen. Rest three elements are metals and hence it forms basic oxide.

Question 14.

Which of the following set of elements is written in order of their increasing metallic character?

(A) Be, Mg, Ca
(B) Na, Li, K
(C) Mg, Al, Si
(D) C,0,N
Answer:
(A) Be, Mg, Ca

Explanation:
As we move down in a group, metallic nature increases. Be, Mg and Ca belong to same group that is group 2 of Modern Periodic table.

Question 15.

Which of the following are the characteristics of isotopes of an element?

(i) Isotopes of an element have same atomic masses.
(ii) Isotopes of an element have same atomic number.
(iii) Isotopes of an element show same physical properties.
(iv) Isotopes of an element show same chemical properties.

(A) (i), (iii) and (iv)
(B) (ii), (iii) and (iv)
(C) (ii) and (iii)
(D) (ii) and (iv) [R
Answer:
(D) (ii) and (iv) [R

Explanation:
Isotopes are the atoms of the same element which have same atomic number but different number of neutrons hence their atomic masses are different.

Question 16.

Which of the following statements is not a correct statement about the trends when going from left to right across the periods of periodic table?

(A) The elements become less metallic in nature
(B) The number of valence electrons increases
(C) The atoms lose their electrons more easily
(D) The oxides become more acidic.
Answer:
(C) The atoms lose their electrons more easily

Explanation:
The atoms lose their electrons more easily. Because on moving from left to right across the periods of the periodic table, the non-metallic character increases. Hence, the tendency to lose electrons decreases.

Assertion and Reason Based MCQs

Question 1.

Assertion (A): Mendeleev arranged element in horizontal rows and vertical columns.
Reason (R): Mendeleev ignored the order of atomic weight thinking that the atomic measurements might be incorrect.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Mendeleev arranged elements in horizontal rows and vertical columns. He ignored the order of atomic weight thinking that the atomic measurements might be incorrect and placed the elements with similar properties.

Question 2.

Assertion (A): Mendeleev left the gap under aluminium and silicon and called these Eka-aluminium and Eka-silicon, respectively. Reason (R): Dobereiner arranged elements on the basis of increasing atomic number.

Answer:
(C) A is true but R is false.

Explanation:
Dobereiner arranged elements on the basis of increasing atomic weights.

Question 3.

Assertion (A): In triad, the three elements have same gaps of atomic masses.
Reason (R): Elements in a triad have similar properties.

Answer:
(D) A is false and R is true.

Explanation:
In a triad, the atomic mass of the middle element is the mean of the atomic masses of the first and third elements.

Question 4.

Assertion (A): According to Mendeleev, periodic properties of elements is a function of their atomic number.
Reason (R): Atomic number is equal to the number of protons.

Answer:
(D) A is false and R is true.

Explanation:
According to Mendeleev, periodic properties of elements is a function of their atomic masses.

Question 5.

Assertion (A): Sixth and seventh periods in the periodic table contains 14 elements.
Reason (R): In the periodic table, 14 elements of sixth and seventh periods are known as lanthanoids and actinoids.

Answer:
(D) A is false and R is true.

Explanation:
Sixth period contains 32 elements and seventh period is incomplete and like sixth, the period would have 32 elements.

Question 6.

Assertion (A): Be and A1 show some similar properties.
Reason (R): The metallic radius of Be is less than the metallic radius of Al.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Be and Al show diagonal relationship because Be resembles in its properties with Al. Metallic radius of the Be (111 pm) is less than the metallic radius of Al (143 pm). Although smaller size is the reason for the anomalous behaviour of Be but not a reason for its diagonal relation with Al.

Question 7.

Assertion (A): The atomic and ionic radii generally decrease towards right in a period.
Reason (R): The ionisation enthalpy increases on moving towards left in a period.

Answer:
(C) A is true but R is false.

Explanation:
The ionisation enthalpy increases on moving towards the extreme right element in period and atomic and ionic radii decreases in a period from left to right.

Question 8.

Assertion (A): Smaller the size of an atom, greater is the electronegativity.
Reason (R): Electronegativity refers to the tendency of atom to share electrons with other atom.

Answer:
(C) A is true but R is false.

Explanation:
Electronegativity refers to the tendency of an atom to attract bonding electrons.

Question 9.

Assertion (A): Noble gases are highly reactive.
Reason (R): Noble gases have stable closed shell electronic configuration.

Answer:
(D) A is false and R is true.

Explanation:
Inert gases (noble gases) are very less reactive due to stable closed shell electronic configuration like ns2, np6 or ns2.

Case-Based MCQs

Attempt any 4 sub-parts from each question. Each sub-part carries 1 mark.
I. Read the passage and answer any four questions from Question 1. to Question 5.
Mendeleev was a Russian chemist, who contributed the most for the development of periodic table of elements wherein the elements were arranged on the basis of their fundamental property, the atomic mass and also on the similarity of chemical properties. Only 63 elements were known at his time. He arranged the 63 elements in the increasing order of their atomic masses and found that there was a periodic recurrence of elements with similar physical and chemical properties. He observed that elements with similar properties fall in the same vertical column. These vertical columns are called groups and horizontal rows of elements are called periods. Mendeleev predicted the existence of certain elements not known at that time and named two of them as Eka-silicon and Eka-aluminium.

Question 1.

Mendeleev arranged the periodic table on the basis of their fundamental property:

(A) Atomic mass
(B) Atomic number
(C) Number of neutrons
(D) Valence electrons
Answer:
(A) Atomic mass

Explanation:
Mendeleev arranged the known elements according to increasing order of their atomic masses because according to him, fundamental property of an element was atomic mass.

Question 2.

Eka aluminium and eka silicon were later replaced respectively as:

(A) Germanium and gallium
(B) Gallium and scandium
(C) Gallium and germanium
(D) Germanium and scandium
Ans.
(C) A is true but R is false.

Explanation:
Mendeleev name unnamed elements as EKA- Boron EKA- Aluminium and EKA Silicon which were later replaced as Scandium, Gallium, and germanium respectively.

Question 3.

The elements eka aluminium and eka silicon discovered by Mendeleev later found place in periodic table. Both of these elements belong to :

(A) Period 2
(B) Group 13
(C) Group 14
(D) Period 4
Answer:
(D) Period 4

Explanation:
Eka silicon replaced with Germanium : Group 14, Period 4 and Eka aluminium replaced with Gallium : Group 13, Period 4.

Question 4.

Mendeleev’s periodic table has :

(A) 8 groups and 7 periods
(B) 7 groups and 8 periods
(C) 7 groups and 7 periods
(D) 8 groups and 8 periods
Answer:
(A) 8 groups and 7 periods

Explanation:
Mendeleev’s periodic table consists of 8 vertical columns called ‘groups’ and 7 horizontal rows called ‘periods’.

Question 5.

How do we classify these newly discovered elements (eka-aluminium and eka-silicon)?

(A) Metals
(B) Non metals
(C) Metalloids
(D) Inert gases
Answer:
(C) Metalloids

Explanation:
The newly discovered elements were metalloids. A metalloid is an element that has properties that are intermediate between those of metals and nonmetals.

Question 1.

Which of these elements have smallest atomic size?

(A) B
(B) C
(C) D
(D) E
Answer:
(D) E

Explanation:
Element E has the smallest atomic size.

Question 2.

Write valency of element E.

(A) 1
(B) 3
(C) 2
(D) 0
Ans.
(C) 2

Explanation:
The valency of element E is 2.

Question 3.

Identify the elements which have similar chemical properties as the element X.

(A) YandZ.
(B) Y and B
(C) All Y, Z and B
(D) None of these
Answer:
(A) YandZ.

Explanation:
Y and Z have similar physical and chemical properties as X.

Question 4.

The number of period that the modern periodic table has

(A) Seven
(B) Eight
(C) Seventeen
(D) Eighteen
Answer:
(A) Seven

Explanation:
There are seven horizontal rows in the modern periodic table. These rows are called periods.

Question 5.

Which of them will have largest atomic radii:

(A) E
(B) X
(C) C
(D) D
Answer:
(B) X

Explanation:
X has the largest atomic radii. It is because atomic radii decrease from left to right along a period.

III. Read the passage and answer any four questions from Question 1. to Question 5.
Atoms of eight elements A, B, C, D, E, F, G and H have the same number of electronic shells but are different in their outermost shells. It was found that elements A and G combine to form an ionic compound which can also be extracted from sea water. Oxides of the elements A and B are basic in nature while those of E and F are acidic. The oxide of elements D is almost neutral.

Question 1.

Which of the following is likely to be halogen?

(A) D
(B) G
(C) H
(D) A
Answer:
(B) G

Explanation:
G belongs to group 17 as it has 7 valence electrons.

Question 2.

Which one of the following elements is likely to be a noble gas?

(A) A
(B) H
(C) D
(D) F
Answer:
(B) H

Explanation:
H belongs to group 18.

Question 3.

Which two elements amongst these are likely to be the non-metals ?

(A) A and G
(B) D and F
(C) E and F
(D) A and B
Answer:
(C) E and F

Explanation:
E and F belong to group 15 and 16 as they form acidic oxides.

Question 4.

Which one of the following will have largest atomic radii?

(A) A
(B) H
(C) G
(D) B
Answer:
(A) A

Explanation:
A has largest atomic radii.

Question 5.

To which period the listed elements belong?

(A) 2nd
(B) 7th
(C) 8th
(D) 3rd
Answer:
(D) 3rd

Explanation:
A and B belong to group 1 and 2 because they form basic oxides. C belongs to group 13 as it has 3 valence electrons. D belongs to group 14 as it forms almost neutral oxide. E and F belong to group 15 and 16 as they form acidic oxides, G belongs to group 17 as it has 7 valence electrons, and H to group 18. They belong to 3rd period of the periodic table.

(A) Lithium
(B) X
(C) Y
(D) Z
Answer:
(D) Z

Explanation:
Z is the most reactive metal.

Question 2.

Name the family of fluorine Q, R, T:

(A) Alkali metals
(B) Noble gas
(C) Halogens
(D) Alkaline metals
Ans.
(C) Halogens

Explanation:
The family of fluorine are Halogen.

Question 3.

Which of the following element belongs to group 2?

(A) Sodium
(B) Magnesium
(C) Aluminium
(D) Carbon
Answer:
(B) Magnesium

Explanation:
Magnesium belong to group 2.

Question 4.

Which other element is likely to present in the group in which fluorine is present:

(A) Neon
(B) Aluminium
(C) Chlorine
(D) None of the above
Answer:
(C) Chlorine

Explanation:
The halogen elements are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts).

Question 5.

Name the element P placed below Carbon in group 14:

(A) Aluminium
(B) Silicon
(C) Phosphorus
(D) Sulphur
Answer:
(B) Silicon

Explanation:
Silicon is the element placed below carbon in group 14.

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 5 Periodic Classification of Elements Read More »

MCQ Questions for Class 10 Science Chapter 4 Carbon and Its Compounds

MCQ Questions / Prasanna

Carbon and Its Compounds Class 10 MCQ Questions With Answers

Question 1.

Which of the following is not observed in a homologous series? Give reason for your choice.

(A) Change in chemical properties
(B) Difference in CH₂ and 14u molecular mass
(C) Gradation in physical properties
(D) Same functional group
Answer:
(A) Change in chemical properties

Explanation:
Change in chemical properties due to presence of same functional group.

Question 2.

Ethane, with the molecular formula C₂H₆ has

(A) 6 covalent bonds
(B) 7 covalent bonds
(C) 8 covalent bonds
(D) 9 covalent bonds
Answer:
(B) 7 covalent bonds

Explanation:
Ethane has 7 covalent bonds. One bond is between two carbon atoms and rest of the six are between hydrogen atoms.

Question 3.

Carbon forms four covalent bonds by sharing its four valence electrons with four univalent atoms, e.g. hydrogen. After the formation of four bonds, carbon attains the electronic configuration of

(A) helium
(B) neon
(C) argon
(D) krypton
Answer:
(B) neon

Explanation:
The nearest inert gas from carbon is Neon. An element try to attain the electronic configuration of its nearest noble gas while attaining a fully-filled outermost shell.

Question 4.

The correct electron dot structure of a water molecule is

Answer:
(C) H :Q: H
Explanation:Oxygen has a complete after octet, while each atom of hydrogen has two electrons in outermost shell.

Question 5.

Oils on treating with hydrogen in the presence of palladium or nickel catalyst form fats. This is an example of

(A) Addition reaction
(B) Substitution reaction
(C) Displacement reaction
(D) Oxidation reaction
Answer:
(A) Addition reaction

Explanation:
Hydrogenation reaction means addition of hydrogen to double bonds of unsaturated compounds found in oil in the presence of catalysts such as palladium or nickel to give saturated hydrocarbons.

Question 6.

When sodium hydrogen carbonate is added to ethanoic acid a gas evolves. Consider the following statements about the gas evolved.

(a) It turns lime water milky.
(b) It is evolved with a brisk effervescence.
(c) It has a smell of burning sulphur.
(d) It is also a byproduct of respiration.

The correct statements are :
(A) (a) and (b) only
(B) (b) and (d) only
(C) (a), (c) and (d)
(D) (a), (b) and (d)
Answer:
(D) (a), (b) and (d)

Explanation:
(a), (b) and (d). The gas evolved is carbon dioxide with brisk effervescence. It turns lime water milky. It is also a by-product of respiration.

Question 7.

While cooking, if the bottom of the vessel is getting blackened on the outside, it means that

(A) the food is not cooked completely.
(B) the fuel is not burning completely.
(C) the fuel is wet.
(D) the fuel is burning completely
Answer:
(B) the fuel is not burning completely.

Explanation:
While cooking, if the bottom of the vessel is getting blackened on the outside, then it means that the fuel is not burning completely.

Assertion and Reason Based MCQs

Question 1.

Assertion (A): In a homologous series of alcohols, the formula for the second member is C₂H₅OH and the third member is C₃H₇OH.
Reason (R): The difference between the molecular masses of the two consecutive members of a homologous series is 14u.

Answer:
(C) A is true but R is false.

Explanation:
In homologous series of alcohols, the formula for the second member is C₂H₅OH and the third member is C₃H₇OH. The difference between the molecular masses of the two consecutive members of a homologous series is 14u.

Question 2.

Assertion (A): Following are the members of a homologous series :
CH₃OH, CH₃CFI₂OH,CH₃CH₂CH₂OHReason (R): A series of compounds with same functional group but differing by CH₂unit is called a homologous series.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Question 3.

Assertion (A): Following are the structural isomers of boutane.

Reason (R): Structural isomers have the same molecular formula but they differ in their structures.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Isomers are defined as those compounds that possess same molecular formula but different structural arrangement. Butane has the molecular formulae C<sub<4H<sub<10. Therefore, the structural isomers of butane will be n-butane and iso-butane.

Question 4.

Assertion (A): Third member of alkane is propane (C₃H₈)
Reason (R): It is obtained from general formula C₂H_{2n + 2}

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
C₃H₈ can be obtained from general formula, C_nH_{2n+ 2}.

Question 5.

Assertion (A): CH₃Cl is obtained from CH₄ by the action of Cl₂ in the presence of sunlight.
Reason (R): It is obtained by addition reaction.

Answer:
(C) A is true but R is false.

Explanation:
CH₃Cl is obtained from CH by substitution reaction by the action of Cl in the I presence of sunlight.

Question 6.

Assertion (A): Most of the carbon compounds are good conductors of electricity.
Reason (R): They do not dissociate to form ions and remain as molecules.

Answer:
(D) A is false and R is true.

Explanation:
Carbon compounds are mainly poor conductors of electricity.

Case-Based MCQs

Attempt any 4 sub-parts from each question. Each sub-part carries 1 mark.

I. Read the passage and answer any four questions from Question l. to Question 5.
A homologous series is a series of organic compounds which belong to the same family (i.e. possess same functional group) and show similar chemical properties. The members of this series are called homologous and differ from each other by the number of CH units in the main carbon chain.

Question 1.

The chemical properties of which of the following compounds is similar to the butane?

(A) Butyne
(B) Propene
(C) Propyne
(D) Pentane
Answer:
(D) Pentane

Explanation:
Methane, ethane, propane, butane, pentane etc. are all part of the alkane homologous series and have similar chemical properties.

Question 2.

The difference between two consecutive members in a homologous series in alkanes in terms of molecular mass and number of atoms of elements is:

(A) 14 a.m.u and CH₂ respectively
(B) 12 a.m.u and CH₃ respectively
(C) 14 a.m.u and CH respectively
(D) 12 a.m.u and CH₃ respectively
Answer:
(A) 14 a.m.u and CH₂ respectively

Explanation:
Homologous series is a series of compounds in which the members present have the same functional group and similar chemical properties and any two successive members in a particular series differ in their molecular formula by a CH₂ unit.

Question 3.

The name and structure of a saturated compound in which 6 carbon atoms are arranged in a ring is :

(A) Hexane
(B) Cyclohexane
(C) Pentane
(D) cyclopentane
Answer:
(B) Cyclohexane

Explanation:
The series like methanol, ethanol, propanol and so on is also a homologous series. The functional group attached to these compounds is alcohol.

Question 4.

Which of the following is not the property of a homologous series?

(A) They show similar chemical properties.
(B) They differ by 14 units by mass.
(C) They all contain double bond
(D) They can be represented by a general formula.
Answer:
(C) They all contain double bond

Explanation:

The characteristics of a homologous series are:
They have same general formula.
Successive compounds differ by CH₂ unit.
Successive compounds have molecular mass difference of 14u.
Molecular mass increases down the series. Therefore members of homologous series show gradation in physical properties such as melting point and boiling points.
Members of homologous series show similar chemical properties.

Question 5.

Which of the following represent the name and formula of the 2nd member of homologous series having general formula C_n H_{2n + 2} ?

(A) Methane CH₄
(B) Ethane C₂H₆
(C) Ethene C₂H₄
(D) Ethyne C₂H₆
Answer:
(B) Ethane C₂ H₆

Explanation:
Methane, ethane, propane, butane, etc. are all part of the alkane homologous series. The general formula of this series is C_nH_2n+2.

II. Read the given passage and answer any of the four questions from Question l. to Question 5.
Carbon has the unique property to form bonds with other atoms of carbon.

Question 1.

Name the characteristic property of carbon as depicted in the fig. A

(A) Catenation
(B) Polymerisation
(C) Isomerisation
(D) None of the above.
Answer:
(A) Catenation
Explanation:
Carbon forms bond with other atoms of carbon. This property of carbon is known as catenation.

Question 2.

Carbon forms large number of compounds due to :

(A) Catenation only
(B) Tetravalency only
(C) Both catenation and tetravalency
(D) None of the above
Answer:
(C) Both catenation and tetravalency

Explanation:
Carbon forms large number of compounds due to the following:
(i) Catenation: Carbon forms bond with other atoms of carbon.
(ii) Tetravalency: Carbon share four electrons with other atoms.

Question 3.

Write the name and structure of a saturated compound in which 6 carbon atoms are arranged in a ring.

(A) Hexane
(B) Cyclohexane
(C) Pentane
(D) cyclopentane
Answer:
(B) Cyclohexane

Explanation:
Cyclohexane is the carbon compounds in which carbon atoms are arranged in the form of a ring. It is a cyclic carbon compounds. Its structure is :

Question 4.

Give the number of single bonds present in the above mentioned compound.

(A) 16
(B) 14
(C) 6
(D) 18
Answer:
(D) 18

Explanation:
The chemical bond formed by the sharing of electrons between the atoms is known as a covalent bond. The total no. of single bonds in cyclohexane (C₆H₁₂) is 18.

Question 5.

Carbon is :

(A) Divalent
(B) Monovalent
(C) tetravalent
(D) Trivalent
Answer:
(C) tetravalent

Explanation:
Carbon has valency of four. It is capable of bonding with four other atoms of carbon or atoms of some other monovalent element. Carbon can form bond with Oxygen, Hydrogen, Nitrogen, Sulphur, Chlorine and many other elements giving rise to compounds with specific properties.

III. Read the passage and answer any four questions Question l. to Question 5.

An organic compound A of molecular formula C₂H₄ on reduction gives another compound B of molecular formula C₂H₆. B on reaction with chlorine in the presence of sunlight gives C of molecular formula C₇H.Cl.

Question 1.

The compounds A, B and C are:

(A) A: ethene B: ethane C: chloroethane
(B) A: ethane B: ethyne C: chloromethane
(C) A: ethyne B: ethane C: chloroethane
(D) A: ethene B: ethyne C: chloroethane
Answer:
(A) A: ethene B: ethane C: chloroethane

Explanation:
The compound is A: CH₂ = CH₂ (Ethene), B is CH₃—CH₃(Ethane) and C is CH₃—CH₂—Cl (Chloroethane)

Question 2.

Unsaturated hydrocarbons undergo…………… reaction.

(A) Substitution
(B) Halogenation
(C) Addition
(D) All of the above
Answer:
(C) Addition

Explanation:
Unsaturated hydrocarbons undergo addition reactions. In unsaturated hydrocarbon, hydrogen added in the presence of catalyst palladium or nickel.

Question 3.

Which of these statements is correct regarding addition reaction?

(A) Addition of hydrogen does not require catalyst.
(B) Multiple bonds (double and triple bonds) must be present between carbon atoms in the chain of hydrocarbon.
(C) Multiple bonds are not required for the reaction to take place.
(D) None of the above.
Answer:
(B) Multiple bonds (double and triple bonds) must be present between carbon atoms in the chain of hydrocarbon.

Explanation:
Essential conditions required for the addition reaction to occur:
(i) Multiple bonds (double and triple bonds) must be present between carbon atoms in the chain of hydrocarbon.
(ii) Addition of hydrogen should be carried out in the presence of catalyst such as nickel or platinum.

Question 4.

The general formula for alkene is:

(A) CnH_2n
(B) CnH_2n+2
(C) CnH_2n-2
(D) CnH_2n+1
Answer:
(A) CnH_2n

Explanation:
The General formula for alkenes are CnH_2n, where n = number of carbon atoms. C₂H₄,C₄H₆,C₄H₈.

Question 5.

Choose the correct condition for conversion of ethene to ethane:

(A) Dehydrogenation at 450°C
(B) Hydrogenation in presence of catalyst like nickel or platinum
(C) Photolytic decomposition
(D) All of the above
Answer:
(B) Hydrogenation in presence of catalyst like nickel or platinum

Explanation:
Hydrogenation of ethene forms ethane in the presence of metal catalyst like Nickel at high temperature. This reaction is called hydrogenation reaction.

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 4 Carbon and Its Compounds Read More »

Case Based MCQ Questions for Class 12 Physical Education Unit 8 Biomechanics and Sports

MCQ Questions / Prasanna

Biomechanics and Sports Class 12 Case Based MCQ Questions

Case-Based Questions

Case Study 1

Altaf, a new student in the school was very much interested / in taking part in the school sports events. He was taught the latest rules and regulations of football game. In due course, he learnt biomechanical aspects of the game including various movements.

Question 1.

The type of movement in which the angle between joint decreases is called:

(a) flexion
(b) extension
(c) gliding
(d) sliding
Answer:
(a) flexion

Question 2.

Straightening parts of a joint so that the angle increases:

(a) flexion
(b) extention
(c) abduction
(d) adduction
Answer:
(b) extention

Question 3.

Moving a part away from mid line is:

(a) flexion
(b) extension
(c) abduction
(d) adduction
Answer:
(c) abduction

Question 4.

Moving a part towards the mid line is:

(a) flexion
(b) extension
(c) abduction
(d) adduction
Answer:
(d) Adduction

Question 5.

Flexion and extension comes under movement.

(a) gliding
(b) angular
(c) rotation
(d) circumduction
Answer:
(b) angular

Case Study 2

Abhishek, the Class 12 monitor, was asked to speak on different types of movements possible in human body and their importance. He talked about four basic movements namely flexion, extension, abduction and adduction. Rest of the movements at different joints are combinations of these four basic movements. He also demonstrated about dorsiflexion and planter flexion movements.

Question 1.

What movement that he demonstrated were possible at the shoulder joint?

(a) Gliding
(b) Angular
(c) circumduction
(d) Rotation
Answer:
(c) Circumduction

Question 2.

At what joint do dorsiflexion and planter flexion movements take place?

(a) Knee joint
(b) Shoulder joint
(c) Ankle joint
(d) Hip joint
Answer:
(c) Ankle joint

Question 3.

Which is the maximum range of movement possible at any joint?

(a) 90 degree
(b) 180 degree
(c) 270 degree
(d) 360 degree
Answer:
(d) 360 degree

Case Study 3

In biomechanics class, Gopi, the teacher, brings the students to the physics lab of his school. The students get confuse(d) After the completion of the class, they realized the fact.

Question 1.

Why does the teacher bring the students to physics lab for biomechanics class?

(a) To explain the principle of Physics
(b) To explain the law of inertia
(c) To discuss about law of acceleration
(d) To explain the law of reaction
Answer:
(a) To explain the principle of Physics

Question 2.

Biomechanics is associated with:

(a) Mechanics
(b) Physics
(c) Mechanics and Physics
(d) Mechanics and Anatomy
Answer:
(d) Mechanics and Anatomy

Question 3.

Biomechanics is the science concerned with the:

(a) internal forces
(b) external forces
(c) Both (a) and (b)
(d) None of these
Answer:
(c) Both (a) and b.

Case Study 4

While talking about Newton’s laws of motion and their application in sports, a Physical Education teacher gave examples from cycling, swimming and cricket. He also told that while cycling, the cyclists only move when they start to pedal and stop only when they apply brakes. While swimming, the swimmers use the wall of the pool to generate the force needed to take off.

Question 1.

Which law is applied to cyclists?

(a) Law of inertia
(b) Law of acceleration
(c) Law of reaction
(d) Law of momentum
Answer:
(a) Law of inertia

Question 2.

Which law is in force when the swimmer pushes off the wall of the swimming pool to start the race?

(a) Law of inertia
(b) Law of acceleration –
(c) Law of reaction
(d) Law of momentum
Answer:
(b) Law of acceleration

Question 3.

Which law is in play when the ball is hit by the batsman?

(a) Law of inertia
(b) Law of acceleration
(c) Law of reaction
(d) Law of momentum
Answer:
(c) Law of reaction.

Case Study 5

During the physical education class Newton’s Laws of motion were discussed and their practical application in sports events was explained to students. These laws are most relevant in sports as most of the actions in sports are related to these laws.

Question 1.

What is the relationship between mass and force?

(a) Directly proportional
(b) No relationship
(c) Inversely proportional
(d) Both (a) and c.
Answer:
(c) Inversely proportional

Question 2.

The acceleration of an object depends inversely upon the object’s:

(a) weight
(b) mass
(c) height
(d) density
Answer:
(b) mass

Question 3.

A high jumper can jump higher off a solid surface because it opposes his or her body with as much force as he or she is able to generate. This example refers to:

(a) Law of conservation
(b) Law of inertia
(c) Law of action and reaction
(d) Law of gravity
Answer:
(c) Law of action and reaction

Case Study 6

The teachers as well as coaches always make their best efforts to improve the performance of their students in various competitive games and sports. They can help to improve the performance of students if they have adequate knowledge of biomechanics.

Question 1.

The more force one exerts on the downward bounce, the higher the ball bounces into the air. Which law in this statement being referred to?

(a) Newton’s 1st law
(b) Newton’s 2nd law
(c) Newton’s 3rd law
(d) Law of gravitation
Answer:
(c) Newton’s 3rd law .

Question 2.

The acceleration of an object depends directly upon the net force acting upon the object and inversely upon the object’s:

(a) weight
(b) mass
(c) height
(d) density
Answer:
(b) mass

Question 3.

The study of human body and various forces acting on it is:

(a) Biology
(b) Biomechanics
(c) Physiology
(d) Anatomy
Answer:
(b) Biomechanics

Case Study 7

Mr Sunder is a Physical Education teacher in a government school. Ramesh, a student is a long jumper but his landing is improper. So he could not win the event on sports day in the school. So Ramesh approached Mr Sunder to seek his help to improve his performance. Mr Sunder explained to Ramesh the proper technique to be followed so as to have the correct body posture while landing. Mr Sunder also motivated Ramesh to constantly practise this technique to perfect it. After the one year of training, Ramesh won the gold medal in the Inter Zonal Athletic Meet.

Question 1.

What was the problem faced by Ramesh?

(a) Improper landing in long jump event
(b) Not winning any medal
(c) improper performance
(d) Incorrect body posture
Answer:
(a) Improper landing in long jump event

Question 2.

Why did Ramesh approached Mr Sunder?

(a) To follow proper technique
(b) To seek help to improve his performance
(c) To win the medal
(d) None of the above
Answer:
(b) To seek help to improve his performance

Question 3.

Mention the reason why Mr Sunder explained Ramesh to follow proper technique.

(a) To have correct body posture
(b) To improve his movements while playing
(c) To have perfection in long jump
(d) So that he could win the medal in the Inter Zonal Athletic Meet
Answer:
(a) To have correct body posture

Assertion-Reason Type Questions

Directions (Q.NOS. 85-94): Each of che following questions consists of two statements, one is Assertion (A) and the other is Reason (R). Select the correct answer to these questions from the codes (a) (b) (c) and (d) as given below:

(a) Both A and R are true and R is correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Question 1.

Assertion (A): Biomechanics plays a vital role in the enhancement of performance of an athlete.
Reason (R): Biom echanics helps the athletes in the prevention of several serious injuries.

Answer:
(a) Both A and R are true and R is correct explanation of A.

Question 2.

Assertion (A): The magnitude of the force of friction depends on the roughness of the surface.
Reason (R): When both the surfaces are smooth, the force of friction reduces to almost zero.

Answer:
(b) Both A and R are true but R is not the correct explanation of A.

Question 3.

Assertion (A): Biomechanics aims to achieve performance enhancement in sports.
Reason (R) : Qualitative analysis helps in technique improvement and injury prevention.

Answer:
(a) Both A and R are true and R is correct explanation of A.

Question 4.

Assertion (A): The primary purpose of biomechanics is to evaluate a living organism’s motion as well as its application of force.
Reason (R) : Biomechanics is the study of forces and their effects on living systems.

Answer:
(b) Both A and R are true but R is not the correct explanation of A.

Question 5.

Assertion (A): Angular motion decreases or increases the angle between two adjoining bones.
Reason (R): Extension is a type of angular motion.

Answer:
(b) Both A and R are true but R is not the correct explanation of A.

Question 6.

Assertion (A): Circumduction takes place between the head of a bone and its articular cavity.
Reason (R) : It is a compound circular movement which involves flexion, extension, adduction and abduction.

Answer:
(b) Both A and R are true but R is not the correct explanation of A.

Question 7.

Assertion (A): Rotation is moving a part around an axis.
Reason (R): Rotation is seen in shoulder and hip joints.

Answer:
(c) A is true but R is false.

Question 8.

Assertion (A): A high jumper can jump higher off a solid surface.
Reason (R): The solid surface opposes his/her body with as much force as he/she is able to generate in contrast to sand or any other unstable surface.

Answer:
(a) Both A and R are true and R is correct explanation of A.

Question 9.

Assertion (A): Law of acceleration is applied in various sports.
Reason (R): If two equal forces are applied to objects of equal mass, the object that has greater force applied will move faster.

Answer:
(c) A is true but R is false.

Question 10.

Assertion (A): Law of acceleration is the second law of motion.
Reason (R) : For every action, there is always an equal and opposite reaction.

Answer:
(b) Both A and R are true but R is not the correct explanation of A.

MCQ Questions for Class 12 Physical Education with Answers

Case Based MCQ Questions for Class 12 Physical Education Unit 8 Biomechanics and Sports Read More »

MCQ Questions

MCQ Questions for Class 10 Science Chapter 9 Heredity and Evolution

Heredity and Evolution Class 10 MCQ Questions With Answers

Which of the following statement is incorrect?

If a round, green seeded pea plant (RRyy) is crossed with wrinkled, yellow seeded pea plant, (rrYY) the seeds produced in F, generation are

The maleness of a child is determined by

A zygote which has an X-chromosome inherited from the father will develop into a

From the list given below, select the character which can be acquired but not inherited.

Two pink coloured flowers on crossing resulted in 1 red, 2 pink and 1 white flower progeny. The nature of the cross will be

A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because

The number of pair (s) of sex chromosomes in the zygote of humans is

In evolutionary terms, we have more in common with

The theory of evolution of species by natural selection was given by

The theory of inheritance of acquired characters was given by

If the fossil of an organism is found in the deeper layers of earth, then we can predict that

Assertion: A geneticist crossed a pea plant having violet flowers with a pea plant having white flowers, he got all violet flowers in first generation. Reason: White colour gene is not passed on to next generation.

Assertion (A): Mendel chose a number of varieties of garden pea as plant material for his experiments. Reason (R): Garden pea has well defined characters and is bisexual.

Assertion (A): In humans, males play an important role in determining the sex of the child. Reason (R): Males have two X chromosomes.

Assertion (A): Learning a skill such as dance and music is an acquired trait. Reason (R): Acquired traits develop in the life time of an individual and do not pass to the progeny.

Assertion (A): Traits like eye colour or height are inherited traits. Reason (R): Inherited traits are not transferred from parents to young ones.

Assertion (A): Fossils are remains of dead organisms. Reason (R): It is helpful in study of evolution.

Assertion (A): Wings of butterfly and wings of bat are analogous orgAnswer: Reason (R): Analogous organs have different origin and structural plan but same function.

Assertion (A): Speciation is the process of formation of a new species from a pre-existing one. Reason (R): Mutation plays a role in speciation.

The above cross is known as:

In a monohybrid cross between two heterozygous individuals, percentage of pure homozygous individuals obtained in F1 generation is ?

Which of these is not the genotype of F progeny?

The ratio of ‘White: Purple’ flowers in the F2 generation is

The missing blank in the above cross is:

The combination of characters in the F2 progeny are:

The ratio of the combination of characters in the F2 progeny is:

A Mendelian experiment consists of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic make-up of the tall parent cod depicted as

What are A-B type of seeds?

A and B are……… traits.

A-D are……… and C-B are ……….. type of seeds.

Which one of these will be produced in minimum and maximum number in the F2 generation?

The above cross is known as

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 8 How do Organisms Reproduce?

How do Organisms Reproduce? Class 10 MCQ Questions With Answers

Reproduction is essential for living organisms in order to

A feature of reproduction that is common to Amoeba, Spirogyra and Yeast are that

In Spirogyra, asexual reproduction takes place by

The ability of a cell to divide into several cells during reproduction in Plasmodium is called

Factors responsible for the rapid spread of bread mould on slices of bread are

In the list of organisms given below, those that reproduce by the asexual method are

Offspring formed by asexual method of reproduction have greater similarity among themselves because

Vegetative propagation refers to formation of new plants from

Asexual reproduction takes place through budding in

Which of the following are examples of vegetative reproduction in plants?

In a flower, the parts that produce male and female gametes (germ cells) are

Which of the following is the correct sequence of events of sexual reproduction in a flower?

The correct sequence of reproductive stages seen in flowering plants is

Which of the following statements are true for flowers?

A student while observing an embryo of a gram seed listed various parts of the embryo as listed below: Testa, Micropyle, Cotyledon, Tegmen, Plumule, Radicle. On examining the list the teacher commented that only three parts are correct. Select these three correct parts:

Characters that are transmitted from parents to offspring during reproduction show

Length of pollen tube depends on the distance between

The number of chromosomes in parents and offsprings of a particular species remains constant due to

During adolescence, several changes occur in the human body. Mark one change associated with sexual maturation in boys.

In human females, an event that reflects onset of reproductive phase is

In human males, the testes lie in the scrotum, because it helps in the

Which among the following is not the function of testes at puberty?

Which of these statement is correct about reproduction ?

The correct sequence of organs in the male reproductive system for transport of sperms is

Which among the following diseases is not sexually transmitted?

Which of the following is not a part of the female reproductive system in human beings?

Assertion (A): Amoeba reproduces by binary fission. Reason (R): All unicellular organisms reproduce asexually.

Assertion (A): Plants are vegetatively propagated even though they bear seeds. Reason (R): Potatoes reproduces through tubers, apples by cutting etc.

Assertion (A): Characteristics of parental plants can be preserved through asexual reproduction. Reason (R): Vegetative reproduction involves only mitosis.

Assertion (A): Plasmodium reproduces by multiple fission. Reason (R): Multiple fission is a type of asexual reproduction.

Assertion (A): DNA copying is necessary during reproduction. Reason (R): DNA copying leads to the transmission of characters from parents to offspring.

Assertion (A): An embryo is formed from fertilized egg Reason (R): A monocot embryo comprises embryo¬nal axis with two cotyledons.

Assertion (A): Unisexual flowers have separate male and female flowers whereas a typical monocot embryo comprises an embryonal axis with single cotyledon. Reason (R): Cucumber, pumpkin and water melon are example of unisexual flowers.

Assertion (A): Double fertilisation is unique to angiosperms. Reason (R): Triple fusion occurs in asexual repro-duction.

Assertion: Fertilization results in formation of zygote. Reason: Zygote divides several times to form an embryo.

Assertion (A): Sexual reproduction increases genetic diversities and plays a role in origin of new species. Reason (R): Sexual reproduction involves formation of gametes and fusion of gametes.

Assertion (A): In human male, testes are extra-abdominal organs which are present inside scrotum. Reason (R): Scrotum has a relatively lower temperature needed for the production and storage of sperms.

Assertion (A): At puberty, in boys, voice begins to crack and thick hair grows on face. Reason (R): At puberty, there is decreased secretion of testosterone in boys.

Assertion (A): Surgical methods are most effective methods of contraception. Reason (R): Surgical method blocks gametes transport and hence prevent fertilisation.

What are common signs of sexual maturation in boys is:

Common sign of sexual maturation in girls is:

Assertion (A): Mendel chose a number of varieties of garden pea as plant material for his experiments.
Reason (R): Garden pea has well defined characters and is bisexual.

Assertion (A): In humans, males play an important role in determining the sex of the child.
Reason (R): Males have two X chromosomes.

Assertion (A): Learning a skill such as dance and music is an acquired trait.
Reason (R): Acquired traits develop in the life time of an individual and do not pass to the progeny.

Assertion (A): Traits like eye colour or height are inherited traits.
Reason (R): Inherited traits are not transferred from parents to young ones.

Assertion (A): Fossils are remains of dead organisms.
Reason (R): It is helpful in study of evolution.

Assertion (A): Wings of butterfly and wings of bat are analogous orgAnswer:
Reason (R): Analogous organs have different origin and structural plan but same function.

Assertion (A): Speciation is the process of formation of a new species from a pre-existing one.
Reason (R): Mutation plays a role in speciation.

In a monohybrid cross between two heterozygous individuals, percentage of pure homozygous individuals obtained in F₁ generation is ?

The ratio of ‘White: Purple’ flowers in the F₂ generation is

The combination of characters in the F₂ progeny are:

The ratio of the combination of characters in the F₂ progeny is:

Which one of these will be produced in minimum and maximum number in the F₂ generation?

Assertion (A): Amoeba reproduces by binary fission.
Reason (R): All unicellular organisms reproduce asexually.

Assertion (A): Plants are vegetatively propagated even though they bear seeds.
Reason (R): Potatoes reproduces through tubers, apples by cutting etc.

Assertion (A): Characteristics of parental plants can be preserved through asexual reproduction.
Reason (R): Vegetative reproduction involves only mitosis.

Assertion (A): Plasmodium reproduces by multiple fission.
Reason (R): Multiple fission is a type of asexual reproduction.

Assertion (A): DNA copying is necessary during reproduction.
Reason (R): DNA copying leads to the transmission of characters from parents to offspring.

Assertion (A): An embryo is formed from fertilized egg
Reason (R): A monocot embryo comprises embryo¬nal axis with two cotyledons.

Assertion (A): Unisexual flowers have separate male and female flowers whereas a typical monocot embryo comprises an embryonal axis with single cotyledon.
Reason (R): Cucumber, pumpkin and water melon are example of unisexual flowers.

Assertion (A): Double fertilisation is unique to angiosperms.
Reason (R): Triple fusion occurs in asexual repro-duction.

Assertion: Fertilization results in formation of zygote.
Reason: Zygote divides several times to form an embryo.

Assertion (A): Sexual reproduction increases genetic diversities and plays a role in origin of new species.
Reason (R): Sexual reproduction involves formation of gametes and fusion of gametes.

Assertion (A): At puberty, in boys, voice begins to crack and thick hair grows on face.
Reason (R): At puberty, there is decreased secretion of testosterone in boys.

Assertion (A): Surgical methods are most effective methods of contraception.
Reason (R): Surgical method blocks gametes transport and hence prevent fertilisation.

Assertion (A): HCl converts pepsinogen into active enzyme pepsin.
Reason (R): Pepsin converts protein into proteoses and peptones.

Assertion (A): Digestion breaks large complex molecules to simple smaller molecules which can be easily absorbed.
Reason (R): Digestion is necessary for the absorption of all molecules.