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Use of pesticides to protect… (Class 10 Science 2024, Q33)

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ScienceCBSE Class 10 · Board exam 2024, set 31/2/1 · 3 marks · Short answer

CBSE Class 10 Science 2024: question 33

Set in the CBSE Class 10 board exam of 2024, paper 31/2/1, section C, question 33, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q33 · 3 marks · Short answerOur Environment

Use of pesticides to protect our crops affect organisms at various trophic levels especially human beings. Name the phenomenon involved and explain how does it happen.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/2/1.

Hints

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

Hint 1

The concentration of a harmful chemical rises as you go up a food chain; what is this called?

Hint 2

Trace the pesticide from the field into the soil, the plants, the animals and then 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. The phenomenon is biological magnification (biomagnification).

    1 mark

  2. Pesticides sprayed on crops are washed down into the soil and water bodies.

    ½ mark

  3. Plants absorb them from the soil along with water and minerals, so the pesticides enter the food chain. Aquatic organisms take them up from water.

    ½ mark

  4. These chemicals are non-biodegradable, so they are not broken down or excreted. They get accumulated progressively at each higher trophic level.

    ½ mark

  5. Human beings occupy the top level in most food chains, so the maximum concentration of these chemicals accumulates in our bodies.

    ½ mark

Answer: Biological magnification: pesticides reach soil and water, enter plants and the food chain, are non-biodegradable and accumulate at each trophic level, reaching the highest concentration in humans.

Where the marks are

  • Names biological magnification (1 mark)
  • Pesticides washed into soil and water (½ mark)
  • Absorbed by plants and enter the food chain (½ mark)
  • Non-biodegradable, so they accumulate at each trophic level (½ mark)
  • Highest concentration in humans at the top of the food chain (½ 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 paper2024 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.