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Assertion (A): The rate… (Class 10 Science SQP 2026-27, Q8)

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ScienceCBSE Class 10 · Sample paper, session 2026-27 · 1 mark · Assertion-reason

CBSE Class 10 Science sample paper 2026-27: question 8

From the official CBSE sample question paper for 2026-27, section A, question 8, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q8 · 1 mark · Assertion-reasonCompetency-basedLife Processes

Assertion (A): The rate of breathing in aquatic organisms is much lower than in the terrestrial organisms. Reason (R): The amount of oxygen dissolved in water is less as compared to the amount of oxygen in air.

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

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2026-27.

Hints

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

Hint 1

If less oxygen is available in water, would a fish need to breathe faster or slower?

Hint 2

Judge A and R separately before linking them.

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. Reason: the amount of oxygen dissolved in water is much less than the amount of oxygen in air. R is true.

  2. Assertion: because water holds so little oxygen, aquatic organisms breathe much faster than terrestrial organisms to get enough oxygen. A says the rate is lower, so A is false.

  3. A is false but R is true, option (D).

    1 mark

Answer: Option (D): A is false but R is true.

Where the marks are

  • Recognises that aquatic animals breathe faster (A false) and that dissolved O₂ is low (R true), option (D) (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 paperSample paper 2026-27: 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.