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Question No. 8 & 9 consists of… (Class 10 Science 2026, Q8)

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ScienceCBSE Class 10 · Board exam 2026, set 31/5/1 · 1 mark · Assertion-reason

CBSE Class 10 Science 2026: question 8

Set in the CBSE Class 10 board exam of 2026, paper 31/5/1, 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-basedHeredity

Question No. 8 & 9 consists of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option from (A), (B), (C) and (D) given below: (A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A). (B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A). (C) Assertion (A) is true, but Reason (R) is false. (D) Assertion (A) is false, but Reason (R) is true.

Assertion (A): Bacteria that can withstand heat have better chances of survival in a heat wave.

Reason (R): Accumulation of variations in a species increases the chances of its survival in changing environment.

  1. (A)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  2. (B)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the 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 2026 board paper, set 31/5/1.

Hints

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

Hint 1

Is heat tolerance an example of a variation?

Hint 2

Ask whether R gives the reason why A happens.

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 true: heat-resistant variants survive a heat wave better than the others.

  2. R is true, and it explains A: the heat tolerance is itself a variation, and variations improve survival in a changing environment. Answer: (A).

    1 mark

Answer: (A)

Where the marks are

  • Both true and R explains A (1 mark)

Revise the chapter

  • Chapter: Heredity (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Heredity, one at a time, marked against the answer key and marking points.Back to the full paper2026 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.