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A tribal farmer is… (Class 12 Biology SQP 2026-27, Q30)

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BiologyCBSE Class 12 · Sample paper, session 2026-27 · 4 marks · Case-based

CBSE Class 12 Biology sample paper 2026-27: question 30

From the official CBSE sample question paper for 2026-27, section D, question 30, for 4 marks. Try it first; the hints and our step-by-step solution are below.

Q30 · 4 marks · Case-basedCompetency-basedBiotechnology and its Applications

A tribal farmer is cultivating Brassica oleracea (cabbage) in a forest region rich in pollinators and rare butterflies. Recently, his crops have been heavily damaged by cabbage looper caterpillars. To manage the pest outbreak, he applies Nucleopolyhedrovirus (NPV). After a few weeks, the pest population decreases significantly without affecting other insects or animals in the area.

  1. A.

    Justify with reasons why the use of Nucleopolyhedrovirus (NPV) was a suitable choice for controlling cabbage looper caterpillars.

    1 mark
  2. B.

    Suggest another IPM strategy suitable for controlling caterpillar pests, and briefly describe its mode of action.

    2 marks
  3. C.

    Name the group of pathogens to which Nucleopolyhedrovirus belong.

    1 mark

  4. OR

    D.

    Justify why the use of NPV is considered a biocontrol method.

    1 mark

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

Focus on why a virus that attacks only one pest suits an area full of butterflies.

Hint 2

Recall the bacterium whose spores are sprayed to kill butterfly caterpillars.

Hint 3

NPV belongs to the virus group named in NCERT's Microbes in Human Welfare chapter.

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. NPV is species-specific and narrow-spectrum. It kills only the target insect pest and does not harm plants, pollinators, rare butterflies, birds, mammals or other non-target insects. This makes it ideal for an ecologically sensitive forest area.

    1 mark

  2. B. Another IPM strategy is to spray spores of the bacterium Bacillus thuringiensis (Bt) on the crop. The caterpillars eat them along with the leaves.

    1 mark

  3. In the alkaline gut of the larvae, the inactive protoxin is converted to the active toxin. This damages the gut lining and kills the larvae.

    1 mark

  4. C. NPV belongs to the Baculoviruses (genus Nucleopolyhedrovirus).

    1 mark

  5. D. (Alternative) NPV is considered biocontrol because it uses a living natural enemy (a pathogen) of the pest, instead of chemicals, to control the pest population.

Answer: A. Species-specific, narrow-spectrum, harmless to non-targets. B. Bt spores: the toxin is activated in the larval gut and kills the larvae. C. Baculoviruses. D. It uses a living organism, not chemicals, to control pests.

Where the marks are

  • NPV is species-specific and narrow-spectrum, with no harm to non-target organisms (1 mark)
  • Names Bacillus thuringiensis spores as an IPM strategy (1 mark)
  • Toxin is released in the larval gut and kills the larvae (1 mark)
  • C: Baculovirus OR D: a biological agent is used instead of chemicals (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Biotechnology and its Applications, 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.