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Choose a correct option that… (Class 12 Biology 2026, Q9)

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BiologyCBSE Class 12 · Board exam 2026, set 57/5/1 · 1 mark · MCQ

CBSE Class 12 Biology 2026: question 9

Set in the CBSE Class 12 board exam of 2026, paper 57/5/1, section A, question 9, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q9 · 1 mark · MCQOrganisms and Populations

Choose a correct option that shows an interaction in which one species benefits while the other is neither harmed nor benefitted.

  1. (A)Mycorrhizal associations between fungi and roots of higher plants
  2. (B)Sea anemone and clownfish
  3. (C)Abingdon tortoises and goats in the Galapagos Island
  4. (D)Cuscuta on hedge plants

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

Name the interaction in which one species gains and the other is unaffected.

Hint 2

Classify each option as mutualism, competition, parasitism or commensalism.

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 +/0 interaction, where one species benefits and the other is unaffected, is called commensalism.

    ½ mark

  2. The clownfish gains protection among the stinging tentacles of the sea anemone, and the anemone gets no benefit or harm. Mycorrhiza is mutualism, the tortoise–goat case is competition and Cuscuta is a parasite. The answer is (B).

    ½ mark

Answer: (B) Sea anemone and clownfish

Where the marks are

  • Identifies commensalism and chooses (B) (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Organisms and Populations, 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.