Skip to content

Study the food chain… (Class 10 Science SQP 2026-27, Q14)

questionbuddy.in/q/cbse-10-science-2026-27-sqp-q14-food-chain

ScienceCBSE Class 10 · Sample paper, session 2026-27 · 3 marks · Short answer

CBSE Class 10 Science sample paper 2026-27: question 14

From the official CBSE sample question paper for 2026-27, section A, question 14, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q14 · 3 marks · Short answerCompetency-basedOur Environment

Study the food chain given below:

  1. A

    In the given food chain, the amount of energy available at the fourth trophic level is 10 kJ, what will be the energy available at the producer level?

    0 marks
  2. B

    Is it possible to have three more trophic levels in the above food chain? Justify.

    0 marks
  3. C

    Which of these trophic levels will have the maximum amount of pesticide, if it had washed down in the water body from agricultural fields. Why?

    0 marks

Figure in the paper: Linear food chain with arrows: Phytoplankton → zooplankton → small fishes → large fish. See it in the official paper.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2026-27.

Hints

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

Hint 1

Use the 10 percent law, working backwards from the 4th level.

Hint 2

If 90% is lost at each step, how much remains after three more steps?

Hint 3

Pesticides cannot be broken down, so where do they collect most?

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. A. By the 10% law, each level gets only 10% of the energy of the level below. Going backwards, multiply by 10 at each step: large fish (4th) = 10 kJ small fishes (3rd) = 100 kJ zooplankton (2nd) = 1000 kJ phytoplankton (1st) = 10000 kJ.

    1 mark

  2. B. No. About 90% of the energy is lost at each step. After three more levels the energy would be kJ, which is far too little usable energy to support organisms. So food chains usually have only 3–4 trophic levels.

    1 mark

  3. C. The large fish (top level) will have the maximum pesticide. Pesticides are non-biodegradable and accumulate at each trophic level. This is called biological magnification, so the highest level holds the greatest concentration.

    1 mark

Answer: A. 10000 kJ; B. No, very little usable energy would remain after 90% loss at each step; C. Large fish, due to biological magnification.

Where the marks are

  • Calculates 10000 kJ at the producer level using the 10% law (1 mark)
  • Says 'No', justified by large energy loss at each level (1 mark)
  • Names large fish and gives biological magnification as the reason (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 paperSample paper 2026-27: 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.