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“Variation is useful for the… (Class 10 Science 2026, Q11)

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ScienceCBSE Class 10 · Board exam 2026, set 31/2/1 · 2 marks · Very short answer

CBSE Class 10 Science 2026: question 11

Set in the CBSE Class 10 board exam of 2026, paper 31/2/1, section A, question 11, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q11 · 2 marks · Very short answerHeredity

“Variation is useful for the survival of species over time.” Explain this statement with the help of an example.

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

What happens to a population if all its members are exactly alike and the environment changes?

Hint 2

Think of bacteria in water that suddenly becomes hotter.

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. Variation means individuals of a species are not all identical. If the environment changes, some variants may be better suited to the new conditions. They survive and reproduce, so the species does not die out.

    1 mark

  2. Example: Suppose a population of bacteria lives in temperate water and the water temperature rises because of global warming. Most bacteria would die, but the few variants that resist heat would survive and multiply. Variation thus allows the species to survive over time.

    1 mark

Answer: Variation gives some individuals traits that let them survive changed conditions, e.g. heat-resistant bacterial variants surviving when water warms.

Where the marks are

  • Explains that variation helps a species survive changing or unfavourable conditions (1 mark)
  • Gives a suitable example such as heat-resistant bacteria surviving a rise in water temperature (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 31/2/1: 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.