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Explain the events that take… (Class 10 Science 2024, Q30)

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ScienceCBSE Class 10 · Board exam 2024, set 31/2/1 · 3 marks · Short answer

CBSE Class 10 Science 2024: question 30

Set in the CBSE Class 10 board exam of 2024, paper 31/2/1, section C, question 30, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q30 · 3 marks · Short answerHow do Organisms Reproduce?

Explain the events that take place once a sperm reaches the oviduct till it becomes a foetus. Write the role of placenta in pregnancy.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/2/1.

Hints

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

Hint 1

Start with what happens when sperm and egg meet, then follow the zygote.

Hint 2

Where does the embryo attach, and which tissue links it to the mother?

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. In the oviduct the sperm meets the egg (ovum), and fertilisation takes place to form a zygote.

    ½ mark

  2. The zygote starts dividing repeatedly and forms a ball of cells, the embryo.

    ½ mark

  3. The embryo moves to the uterus and is implanted in the thick, blood-rich lining of the uterus.

    ½ mark

  4. There it keeps growing and develops organs, and it becomes a foetus.

    ½ mark

  5. Role of placenta (1): The placenta is a disc-like tissue embedded in the uterine wall. Its villi give a large surface area for glucose and oxygen to pass from the mother's blood to the embryo.

    ½ mark

  6. Role of placenta (2): Wastes produced by the embryo are passed into the mother's blood through the placenta for removal.

    ½ mark

Answer: Fertilisation in the oviduct gives a zygote, which divides to form an embryo; the embryo implants in the uterine lining and develops organs to become a foetus. The placenta supplies glucose and oxygen to the embryo and removes its wastes into the mother's blood.

Where the marks are

  • Fertilisation in the oviduct (½ mark)
  • Zygote divides to form a ball of cells, the embryo (½ mark)
  • Implantation in the uterine lining (½ mark)
  • Develops organs and becomes a foetus (½ mark)
  • Placenta passes glucose and oxygen to the embryo over a large surface area (½ mark)
  • Placenta removes the embryo's wastes into the mother's blood (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 paper2024 board paper, set 31/2/1: 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.