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"Excessive use of chemicals… (Class 10 Science 2025, Q26)

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ScienceCBSE Class 10 · Board exam 2025, set 31/1/1 · 2 marks · Very short answer

CBSE Class 10 Science 2025: question 26

Set in the CBSE Class 10 board exam of 2025, paper 31/1/1, section B, question 26, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q26 · 2 marks · Very short answerCompetency-basedOur Environment

"Excessive use of chemicals and pesticides in agriculture adversely effect the environment." Justify this statement.

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

Hints

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

Hint 1

Where do the pesticides go after rain?

Hint 2

Can decomposers break these chemicals down? What happens to them in a food chain?

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. Chemical fertilisers and pesticides sprayed on crops get washed by rain into the soil and water bodies. There they harm both the biotic components (plants, animals, microbes) and the abiotic components (soil, water) of the ecosystem.

    1 mark

  2. Most of these chemicals are non-biodegradable. They enter food chains and build up in increasing concentration at each higher trophic level. This is called biological magnification. Organisms at all trophic levels, including humans at the top, therefore suffer harmful health effects. So the statement is justified.

    1 mark

Answer: Chemicals wash into soil and water, are non-biodegradable, and accumulate at each trophic level (biological magnification), harming all organisms.

Where the marks are

  • Chemicals reach soil and water bodies and harm biotic and abiotic components (1 mark)
  • Non-biodegradable chemicals accumulate along food chains (biological magnification), affecting all trophic levels (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 paper2025 board paper, set 31/1/1: 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.