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What are decomposers? Give… (Class 10 Science 2025, Q33)

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ScienceCBSE Class 10 · Board exam 2025, set 31/4/1 · 3 marks · Short answer

CBSE Class 10 Science 2025: question 33

Set in the CBSE Class 10 board exam of 2025, paper 31/4/1, 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

What are decomposers? Give two examples. State how they maintain a balance in an ecosystem.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/4/1.

Hints

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

Hint 1

Think about what would happen to dead leaves and animals if nothing broke them down.

Hint 2

Where do the products of decomposition go, and who uses them next?

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. Decomposers are microorganisms that break down the complex organic substances in dead plants and animals into simple inorganic substances.

    1 mark

  2. Examples: bacteria and fungi.

    1 mark

  3. The simple substances they release go into the soil and are used again by plants. This recycles nutrients, cleans away dead matter and keeps the ecosystem in balance.

    1 mark

Answer: Decomposers (e.g. bacteria and fungi) break down dead organic matter into simple substances that return to the soil for reuse by plants, maintaining balance in the ecosystem.

Where the marks are

  • Correct definition of decomposers (1 mark)
  • Two examples, bacteria and fungi (½ + ½ mark)
  • Role in recycling nutrients to the soil for plants (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 31/4/1: 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.