Class 10 Science · Chapter 7

How do Organisms Reproduce?

185 Class 10 Science questions on How do Organisms Reproduce? from the NCERT textbook, NCERT Exemplar and CBSE board papers 2024–2026, each with its answer and a step-by-step solution.

CBSE Class 10 Science previous year papers, with answers →

Questions · page 2 of 10

1. Q21 NCERT · Intext Questions (Page 126)
   What ​are the changes seen ​in girls ​at the ​time ​of ​puberty?
   Show answer

   In girls puberty brings body hair, oily skin and pimples, breast enlargement with darker nipples, the start of menstruation and new body awareness.

   The changes fall into two groups. (i) Changes common to girls and boys: thick hair begins to grow in new parts of the body, in the armpits and in the genital area between the thighs, and the skin there can also become darker; thinner hair appears on the legs and arms and on the face; the skin frequently becomes oily and pimples may develop; and there is a new consciousness and awareness of one's own body and of the bodies of others. (ii) Changes seen in girls in particular: the breast size begins to increase, with darkening of the skin of the nipples at the tips of the breasts, and girls begin to menstruate at around this time. All these changes take place slowly, over months and years. They do not happen all at once, nor at an exact age, and they differ from one girl to another. Every one of them is an aspect of the sexual maturation of the body, which begins during adolescence, when the rate of general body growth slows down and the reproductive tissues begin to mature.

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2. Q22 NCERT · Intext Questions (Page 126)
   How ​does ​the embryo ​get ​nourishment ​inside the ​mother's ​body?
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   The embryo is nourished through the placenta, where glucose and oxygen pass from the mother's blood to it and its wastes pass back.

   Through the placenta. After fertilisation the zygote divides to form a ball of cells, and this embryo is implanted in the lining of the uterus, which has thickened and become richly supplied with blood to nourish it. The embryo then gets its nutrition from the mother's blood with the help of a special tissue called the placenta, a disc embedded in the uterine wall and joined to the embryo by the umbilical cord. The placenta contains villi on the embryo's side of the tissue, and on the mother's side are blood spaces which surround these villi. Because the finger-like villi dip into pools of the mother's blood, the arrangement provides a large surface area, so that glucose and oxygen can pass in quantity from the mother to the embryo. The traffic runs both ways: the waste substances that the developing embryo generates are removed by transferring them into the mother's blood through the same placenta. In this way the placenta feeds the embryo, supplies it with oxygen and carries its wastes away for the roughly nine months of development, doing the work that the digestive system, the lungs and the kidneys will take over after birth.

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3. Q23 NCERT · Intext Questions (Page 126)
   If a woman ​is using ​a copper-T, will ​it help ​in ​protecting her from sexually ​transmitted diseases?
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   No; the copper-T only prevents pregnancy, while a condom protects against both pregnancy and infection.

   No, it will not. The copper-T is a contraceptive device placed inside the uterus, and its only effect is to prevent pregnancy; it can also cause side effects due to irritation of the uterus. Sexually transmitted diseases, such as the bacterial infections gonorrhoea and syphilis and the viral infections warts and HIV-AIDS, are passed on because the sexual act is a very intimate connection of bodies, so the germs cross where the two bodies touch and exchange fluids. The copper-T covers neither the penis nor the vaginal passage, so it leaves that contact entirely unaffected and the germs pass exactly as they would without it. Protection from these infections needs a barrier method instead: using a covering called a condom for the penis during sex helps to prevent the transmission of many of them to some extent, and a similar covering worn in the vagina serves the same purpose. So the copper-T guards against pregnancy alone, while a condom guards against both pregnancy and infection.

   Step-by-step solution →
4. Q24 Exemplar · Multiple Choice Questions
   In ​the list of ​organisms given below, those ​that reproduce by ​the asexual ​method are

   1. (i)banana
   2. (ii)​dog
   3. (iii)​yeast
   4. (iv)Amoeba

   1. (a)(ii) and (iv)
   2. (b)(i), (iii) and (iv)
   3. (c)(i) and (iv)
   4. (d)(ii), (iii) and (iv)
   Show answer

   (b) (i), (iii) and (iv)

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5. Q25 Exemplar · Multiple Choice Questions
   In ​a flower, ​the parts ​that ​produce ​male ​and ​female gametes (germ cells) are

   1. (a)stamen and anther
   2. (b)filament and stigma
   3. (c)anther and ovary
   4. (d)stamen and style
   Show answer

   (c) anther and ovary

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6. Q26 Exemplar · Multiple Choice Questions
   Which of ​the ​following is the ​correct sequence of events ​of sexual reproduction ​in a flower?

   1. (a)pollination, fertilisation, seedling, embryo
   2. (b)seedling, embryo, fertilisation, pollination
   3. (c)pollination, fertilisation, embryo, seedling
   4. (d)embryo, seedling, pollination, fertilisation
   Show answer

   (c) pollination, fertilisation, embryo, seedling

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7. Q27 Exemplar · Multiple Choice Questions
   Offspring formed by asexual method ​of reproduction have ​greater similarity among themselves because

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

   1. (a)(i) and (ii)
   2. (b)(i) and (iii)
   3. (c)(ii) and (iv)
   4. (d)(iii) and (iv)
   Show answer

   (a) (i) and (ii)

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8. Q28 Exemplar · Multiple Choice Questions
   Characters ​transmitted from ​parents ​to offspring are present ​in

   1. (a)cytoplasm
   2. (b)ribosome
   3. (c)golgi bodies
   4. (d)genes
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   (d) genes

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9. Q29 Exemplar · Multiple Choice Questions
   Characters that ​are ​transmitted ​from ​parents ​to offspring ​during ​reproduction ​show

   1. (a)only similarities with parents
   2. (b)only variations with parents
   3. (c)both similarities and variations with parents
   4. (d)neither similarities nor variations
   Show answer

   (c) both similarities and variations with parents

   Step-by-step solution →
10. Q30 Exemplar · Multiple Choice Questions
    A feature of reproduction that ​is ​common to Amoeba, ​Spirogyra and Yeast ​is that

    1. (a)they reproduce asexually
    2. (b)they are all unicellular
    3. (c)they reproduce only sexually
    4. (d)they are all multicellular
    Show answer

    (a) they reproduce asexually

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11. Q31 Exemplar · Multiple Choice Questions
    In ​Spirogyra, ​asexual reproduction ​takes ​place ​by

    1. (a)breaking up of filaments into smaller bits
    2. (b)division of a cell into two cells
    3. (c)division of a cell into many cells
    4. (d)formation of young cells from older cells.
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    (a) breaking up of filaments into smaller bits

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12. Q32 Exemplar · Multiple Choice Questions
    The ​ability of ​a cell ​to divide ​into ​several ​cells ​during reproduction in Plasmodium is called

    1. (a)budding
    2. (b)reduction division
    3. (c)binary fission
    4. (d)multiple fission
    Show answer

    (d) multiple fission

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13. Q33 Exemplar · Multiple Choice Questions
    The ​correct ​sequence ​of ​reproductive ​stages seen ​in flowering plants ​is

    1. (a)gametes, zygote, embryo, seedling
    2. (b)zygote, gametes, embryo, seedling
    3. (c)seedling, embryo, zygote, gametes
    4. (d)gametes, embryo, zygote, seedling
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    (a) gametes, zygote, embryo, seedling

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14. Q34 Exemplar · Multiple Choice Questions
    The ​number ​of chromosomes ​in parents and ​offsprings ​of a particular species remains constant due to

    1. (a)doubling of chromosomes after zygote formation
    2. (b)halving of chromosomes during gamete formation
    3. (c)doubling of chromosomes after gamete formation
    4. (d)halving of chromosomes after gamete formation
    Show answer

    (b) halving of chromosomes during gamete formation

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15. Q35 Exemplar · Multiple Choice Questions
    In ​Rhizopus, ​tubular ​thread-like structures ​bearing ​sporangia ​at their tips ​are called

    1. (a)filaments
    2. (b)hyphae
    3. (c)rhizoids
    4. (d)roots
    Show answer

    (b) hyphae

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16. Q36 Exemplar · Multiple Choice Questions
    Vegetative ​propagation ​refers ​to ​formation of new ​plants ​from

    1. (a)stem, roots and flowers
    2. (b)stem, roots and leaves
    3. (c)stem, flowers and fruits
    4. (d)stem, leaves and flowers
    Show answer

    (b) stem, roots and leaves

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17. Q37 Exemplar · Multiple Choice Questions
    Factors responsible ​for the rapid ​spread of bread mould ​on slices of bread are

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

    1. (a)(i) and (iii)
    2. (b)(ii) and iv)
    3. (c)(i) and (ii)
    4. (d)(iii) and (iv)
    Show answer

    (c) (i) and (ii)

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18. Q38 Exemplar · Multiple Choice Questions
    Length ​of ​pollen ​tube ​depends ​on ​the distance ​between

    1. (a)pollen grain and upper surface of stigma
    2. (b)pollen grain on upper surface of stigma and ovule
    3. (c)pollen grain in anther and upper surface of stigma
    4. (d)upper surface of stigma and lower part of style
    Show answer

    (b) pollen grain on upper surface of stigma and ovule

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19. Q39 Exemplar · Multiple Choice Questions
    Which of the following statements are true for flowers?

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

    1. (a)(i) and (iv)
    2. (b)(ii) and (iii)
    3. (c)(i) and (iii)
    4. (d)(ii) and (iv)
    Show answer

    (d) (ii) and (iv)

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20. Q40 Exemplar · Multiple Choice Questions
    Which among the following statements are ​true ​for unisexual flowers?

    1. (i)​They ​possess ​both stamen and ​pistil
    2. (ii)They possess either stamen or pistil
    3. (iii)​They exhibit cross pollination
    4. (iv)​Unisexual flowers possessing only stamens cannot produce fruits

    1. (a)(i) and (iv)
    2. (b)(ii), (iii) and (iv)
    3. (c)(iii) and (iv)
    4. (d)(i), (iii) and (iv)
    Show answer

    (b) (ii), (iii) and (iv)

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