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Tag: CHAPTER 7 How do Organisms Reproduce?

  • Class 10th Science Chapter 7 – How do Organisms Reproduce? – Exercises

    Q1. Asexual reproduction takes place through budding in

    (a) Amoeba
    (b) Yeast
    (c) Plasmodium
    (d) Leishmania

    Answer: (b) Yeast

    Explanation:

    • Yeast reproduces asexually by budding, where a small outgrowth (bud) forms and grows into a new individual.

    • Amoeba → binary fission

    • Plasmodium → multiple fission

    • Leishmania → binary fission (longitudinal)

    Q2. 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 a part of the male reproductive system, which carries sperm.

    • Ovary, uterus and fallopian tube are parts of the female reproductive system.

    Q3. The anther contains

    (a) sepals
    (b) ovules
    (c) pistil
    (d) pollen grains

    Answer: (d) Pollen grains

    Explanation:

    • Anther is a part of the male reproductive organ (stamen) in flowers.

    • It produces pollen grains, which contain male gametes.

    • Ovules are found in ovary (female part).

    Q4. What are the advantages of sexual reproduction over asexual reproduction?

    Answer:

    Sexual reproduction has several advantages:

    • Produces variations in offspring

    • Helps in evolution and development of better-adapted organisms

    • Ensures greater survival in changing environmental conditions

    • Results in offspring that are genetically different from parents

    Conclusion

    Sexual reproduction improves the survival and stability of a species.

    Q5. What are the functions performed by the testis in human beings?

    Answer:

    Testis performs two main functions:

    1. Production of sperms (male reproductive cells)

    2. Production of testosterone hormone, which:

      • controls the development of male sexual features

      • regulates sperm production

    Q6. Why does menstruation occur?

    Answer:

    If fertilisation does not occur, the thick lining of the uterus breaks down and comes out through the vagina along with blood and tissue.
    This process is called menstruation.

    Occurs once every 28 days approximately.

    Q7. Draw a labelled diagram of the longitudinal section of a flower.

    Answer (description for notebook):

    A labelled diagram must include:

    • Petal
    • Sepal
    • Stamen (Anther + Filament)
    • Carpel / Pistil (Stigma, Style, Ovary)
    • Ovule
    • Receptacle

    Q8. What are the different methods of contraception?

    Answer:

    Different methods of contraception include:

    1. Barrier methods

    • Condom, diaphragm

    • Prevent sperm from reaching egg

    2. Chemical / Hormonal methods

    • Oral pills

    • Injections

    • Prevent ovulation

    3. Intrauterine devices (IUDs)

    • Copper-T, Loop

    • Placed inside uterus to block sperm entry

    4. Surgical methods

    • Vasectomy (males – cutting vas deferens)

    • Tubectomy (females – cutting fallopian tubes)

    5. Natural methods

    • Withdrawal method

    • Rhythm / safe period method

    Q9. How are the modes for reproduction different in unicellular and multicellular organisms?

    Answer:

    Unicellular organisms Multicellular organisms
    Reproduce by asexual methods such as binary fission, budding, multiple fission Reproduce mostly by sexual reproduction
    One parent is involved

    Two parents (male & female) are usually involved
    Offspring are genetically identical to parent

    Offspring show variations
    Simple and fast process

    Complex and slower process
    Example: Amoeba, Yeast Example: Humans, Animals, Flowering plants

    Q10. How does reproduction help in providing stability to populations of species?

    Answer:

    Reproduction helps maintain the population of a species by:

    • Replacing individuals that die

    • Producing new individuals to continue species existence

    • Providing variations which help organisms adapt and survive environmental changes

    Conclusion:

    Without reproduction, species would disappear over time.

    Q11. What could be the reasons for adopting contraceptive methods?

    Answer:

    Contraceptive methods are adopted to:

    • Prevent unwanted or unplanned pregnancies

    • Control population growth

    • Maintain the health of the mother

    • Allow proper spacing between children

    • Prevent transmission of sexually transmitted diseases (STDs) (e.g., HIV, AIDS, Syphilis) – by using condoms

    • Improve economic and social conditions of the family