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Assertion (A): In large… (Class 10 Science 2025, Q17)

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ScienceCBSE Class 10 · Board exam 2025, set 31/4/1 · 1 mark · Assertion-reason

CBSE Class 10 Science 2025: question 17

Set in the CBSE Class 10 board exam of 2025, paper 31/4/1, section A, question 17, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q17 · 1 mark · Assertion-reasonCompetency-basedLife Processes

Assertion (A): In large animals, oxygen can reach different parts of the animal's body easily.

Reason (R): Respiratory pigments take up oxygen from the air and carry it to body tissues.

Options: (a) Both A and R are true, and R is the correct explanation of A. (b) Both A and R are true, and R is not the correct explanation of A. (c) A is true, but R is false. (d) A is false, but R is true.

  1. (A)Both, Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  2. (B)Both, Assertion (A) and Reason (R) are true, and Reason (R) is not the correct explanation of Assertion (A).
  3. (C)Assertion (A) is true, but Reason (R) is false.
  4. (D)Assertion (A) is false, but Reason (R) is true.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/4/1.

Hints

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

Hint 1

Is diffusion enough to supply oxygen in a large body?

Hint 2

What does haemoglobin do?

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 is false: in large animals, diffusion alone cannot deliver oxygen to all body parts easily.

  2. R is true: respiratory pigments such as haemoglobin take up oxygen and carry it to the tissues. Option (D).

    1 mark

Answer: (D) A false, R true

Where the marks are

  • A false, R true (1 mark)

Revise the chapter

  • Chapter: Life Processes (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Life Processes, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 31/4/1: 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.