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Differentiate between… (Class 12 Biology 2026, Q21a)

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BiologyCBSE Class 12 · Board exam 2026, set 57/5/1 · 2 marks · Very short answer

CBSE Class 12 Biology 2026: question 21(a)

Set in the CBSE Class 12 board exam of 2026, paper 57/5/1, section B, question 21(a), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q21(a) · 2 marks · Very short answerEcosystem

Differentiate between grazing food chain and detritus food chain.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 57/5/1.

Hints

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

Hint 1

Compare the first link (starting point) of each chain.

Hint 2

Think about which chain carries more energy in a lake and which in a forest.

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. Grazing food chain (GFC)Detritus food chain (DFC)
    Starts with producers (green plants).Starts with dead organic matter (detritus) and its decomposers.
    1 mark
  2. Grazing food chain (GFC)Detritus food chain (DFC)
    Major conduit of energy flow in aquatic ecosystems.Major conduit of energy flow in terrestrial ecosystems.
    1 mark

Answer: GFC starts from producers and is the major energy route in aquatic ecosystems. DFC starts from detritus and is the major energy route in terrestrial ecosystems.

Where the marks are

  • First correct difference, e.g. starting point: producers vs detritus (1 mark)
  • Second correct difference, e.g. major energy conduit in aquatic vs terrestrial ecosystems, or energy fraction carried (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Ecosystem, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 57/5/1: 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.