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Given below are… (Class 10 Science SQP 2023-24, Q35a)

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ScienceCBSE Class 10 · Sample paper, session 2023-24 · 5 marks · Long answer

CBSE Class 10 Science sample paper 2023-24: question 35(a)

From the official CBSE sample question paper for 2023-24, section D, question 35(a), for 5 marks. Try it first; the hints and our step-by-step solution are below.

Q35(a) · 5 marks · Long answerCompetency-basedHow do Organisms Reproduce?

Given below are certain situations. Analyze and describe its possible impact on a person:

  1. (a)

    Testes of a male boy are not able to descend into scrotum during his embryonic development.

    1 mark
  2. (b)

    Vas deferens of a man is plugged.

    1 mark
  3. (c)

    Prostate and seminal vesicles are not functional.

    1 mark
  4. (d)

    Egg is not fertilised in a human female.

    1 mark
  5. (e)

    Placenta does not attach to the uterus optimally.

    1 mark

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2023-24.

Hints

Open one hint at a time and try again before the next.

Hint 1

For each part, first recall the normal job of the organ or event mentioned.

Hint 2

Then think about what fails if that job is not done. For example: why are the testes kept outside the body, and what does the placenta supply to the embryo?

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. (a) Testes do not descend into the scrotum: Sperm formation needs a temperature slightly lower than normal body temperature. The scrotum keeps the testes outside the body cavity for this reason. If the testes stay inside the abdomen, they are at body temperature, so sperm formation is badly affected. The person may be infertile.

    1 mark

  2. (b) Vas deferens plugged: The vas deferens carries sperms from the testis towards the urethra. If it is blocked, sperms cannot be carried out and will not be present in the semen. The man cannot fertilise an egg. This is the basis of vasectomy, a surgical method of contraception.

    1 mark

  3. (c) Prostate and seminal vesicles not functional: These glands add their secretions to the sperms. The secretions provide nourishment and a fluid medium in which sperms can move and be transported. Without them, sperms will be poorly nourished and will not be transported easily, so fertility is reduced.

    1 mark

  4. (d) Egg not fertilised: The unfertilised egg survives for about one day. The thick, blood-rich lining of the uterus is then not needed. It breaks down and comes out through the vagina as blood and mucus along with the egg. This is menstruation, which occurs roughly every month.

    1 mark

  5. (e) Placenta not attached to the uterus properly: The placenta passes glucose and oxygen from the mother's blood to the embryo and removes the embryo's wastes. Poor attachment means the embryo gets too little nutrition and oxygen. Its growth and development are affected, which may even cause serious complications such as loss of the pregnancy.

    1 mark

Answer: (a) Sperm formation affected because the testes are at body temperature. (b) Sperms cannot be transported, so no sperms in semen. (c) No secretions for nourishment and transport of sperms. (d) Uterine lining breaks down and menstruation occurs. (e) Embryo gets less nutrition and oxygen, so its growth is affected.

Where the marks are

  • States sperm formation is affected because it needs a temperature lower than body temperature (1 mark)
  • States sperms cannot be transferred further when the vas deferens is blocked (1 mark)
  • States sperms will lack the secretions that give nourishment and a medium for transport (1 mark)
  • Explains that the uterine lining breaks down, leading to menstruation (1 mark)
  • States the embryo will not get proper nutrition and oxygen, affecting its growth (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from How do Organisms Reproduce?, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2023-24: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.