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Answer the following. (Class 10 Science 2023, Q35a)

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ScienceCBSE Class 10 · Board exam 2023, set 31/5/1 · 5 marks · Long answer

CBSE Class 10 Science 2023: question 35(a)

Set in the CBSE Class 10 board exam of 2023, paper 31/5/1, 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 answerHow do Organisms Reproduce?

Answer the following.

  1. (i)

    Where are testes located in the human males and why ? State two function of the testes.

    0 marks
  2. (ii)

    In the human female, one of the ovaries releases an egg every month. State the changes that take place if (1) the egg is fertilized, and (2) the egg is not fertilized.

    0 marks
  3. (iii)

    What is done during the surgical method in males and females to prevent pregnancy ?

    0 marks

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/5/1.

Hints

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

Hint 1

Why might sperm-producing organs hang outside the body cavity? Think about temperature.

Hint 2

The uterus prepares a thick lining every month. What happens to it with and without an embryo?

Hint 3

Surgical methods block the tube that carries the gametes in each sex.

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. (i) The testes are located outside the abdominal cavity, in the scrotum.

    ½ mark

  2. Reason: sperm formation needs a temperature lower than normal body temperature.

    ½ mark

  3. Function 1: formation of sperms (male gametes).

    ½ mark

  4. Function 2: secretion of the male sex hormone testosterone.

    ½ mark

  5. (ii)(1) If the egg is fertilised, the zygote divides repeatedly to form an embryo. The embryo gets implanted in the thickened, blood-rich lining of the uterus and develops further, nourished through the placenta.

    1 mark

  6. (2) If the egg is not fertilised, the thick inner lining of the uterus is no longer needed. It slowly breaks down and comes out through the vagina as blood and mucus (menstruation), roughly every month.

    1 mark

  7. (iii) In males, the vas deferens is blocked or cut (vasectomy) so that sperms cannot be transferred.

    ½ mark

  8. In females, the fallopian tube (oviduct) is blocked or cut (tubectomy) so that the egg cannot reach the uterus.

    ½ mark

Answer: (i) In the scrotum, outside the abdomen, as sperm formation needs a lower temperature; functions: sperm formation and testosterone secretion; (ii)(1) zygote forms embryo, which implants in the uterus lining; (2) uterine lining breaks down and is shed as menstruation; (iii) vasectomy (vas deferens blocked) and tubectomy (fallopian tube blocked)

Where the marks are

  • Location: scrotum, outside the abdominal cavity (½ mark)
  • Reason: sperm formation needs a lower temperature (½ mark)
  • Function: sperm formation (½ mark)
  • Function: testosterone production (½ mark)
  • Fertilised egg: zygote forms embryo and implants in uterine lining (1 mark)
  • Unfertilised egg: uterine lining breaks down and comes out as blood and mucus (1 mark)
  • Vasectomy: vas deferens blocked (½ mark)
  • Tubectomy: fallopian tube blocked (½ 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 paper2023 board paper, set 31/5/1: 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.