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Assertion (A) : There are… (Class 10 Science 2026, Q9)

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ScienceCBSE Class 10 · Board exam 2026, set 31/2/1 · 1 mark · Assertion-reason

CBSE Class 10 Science 2026: question 9

Set in the CBSE Class 10 board exam of 2026, paper 31/2/1, section A, question 9, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q9 · 1 mark · Assertion-reasonCompetency-basedOur Environment

Assertion (A) : There are generally a greater number of individuals at the lower trophic levels of an ecosystem.
Reason (R) : The greatest number is of the producers.

  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, but 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 2026 board paper, set 31/2/1.

Hints

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

Hint 1

Check whether each statement is true on its own.

Hint 2

Does R give the cause, or just another fact?

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. Both statements are true. Lower trophic levels hold more individuals, and producers are the most numerous.

  2. R only restates a fact about one level. It does not explain why numbers are greater at lower levels; the explanation is the energy loss at each transfer. So R is not the correct explanation. Option (B).

    1 mark

Answer: Option (B)

Where the marks are

  • Recognises both true but R does not explain A (1 mark)

Revise the chapter

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