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Use of several pesticides… (Class 10 Science 2023, Q26)

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ScienceCBSE Class 10 · Board exam 2023, set 31/4/1 · 2 marks · Very short answer

CBSE Class 10 Science 2023: question 26

Set in the CBSE Class 10 board exam of 2023, paper 31/4/1, 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

Use of several pesticides which results in excessive accumulation of pesticides in rivers or ponds, is a matter of deep concern. Justify this statement.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/4/1.

Hints

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

Hint 1

Can microbes break down most pesticides?

Hint 2

Think of what happens to such a chemical as it passes from plankton to fish to humans.

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. Many pesticides are non-biodegradable. They are not broken down and get washed into rivers and ponds, where aquatic plants and animals absorb them.

    1 mark

  2. These chemicals pass along the food chain and become more concentrated at each higher trophic level. This is biological magnification. Top consumers, including humans who eat fish, receive the highest dose, which harms their health. Hence it is a matter of deep concern.

    1 mark

Answer: Non-biodegradable pesticides enter food chains and concentrate at each trophic level (biomagnification), harming top consumers including humans.

Where the marks are

  • Pesticides are non-biodegradable and enter the food chain (1 mark)
  • Concentration increases at each trophic level: biomagnification affecting humans (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 paper2023 board paper, set 31/4/1: 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.