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Answer the following. (Class 12 Biology 2023, Q20a)

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BiologyCBSE Class 12 · Board exam 2023, set 57/5/1 · 2 marks · Very short answer

CBSE Class 12 Biology 2023: question 20(a)

Set in the CBSE Class 12 board exam of 2023, paper 57/5/1, section B, question 20(a), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q20(a) · 2 marks · Very short answerMicrobes in Human Welfare

Answer the following.

  1. (i)

    Give an example of a genus of virus used as narrow spectrum insecticidal biocontrol agent.

    0 marks
  2. (ii)

    How does its use serve as an aid in overall integrated pest management programme ?

    0 marks

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 57/5/1.

Hints

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

Hint 1

The answer belongs to the baculovirus group studied under biocontrol agents.

Hint 2

For (ii), think about what happens to organisms other than the pest when this virus is used.

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. (i) Nucleopolyhedrovirus (a baculovirus) is used as a narrow-spectrum insecticidal biocontrol agent.

    1 mark

  2. (ii) It is species-specific, with narrow-spectrum action. It attacks only the target insect pest and has no harmful effect on plants, mammals, birds, fish or non-target insects.

    ½ mark

  3. Because beneficial insects are spared, it is ideal for integrated pest management, especially in ecologically sensitive areas.

    ½ mark

Answer: (i) Nucleopolyhedrovirus (Baculovirus); (ii) It is species-specific, harms no non-target organisms and conserves beneficial insects, so it suits IPM in ecologically sensitive areas.

Where the marks are

  • Names Nucleopolyhedrovirus as the genus (1 mark)
  • States it is species-specific / narrow-spectrum in action (½ mark)
  • States it does not harm non-target organisms, conserves beneficial insects, or suits ecologically sensitive areas (½ mark)

Revise the chapter

Practise this chapterBoard-style questions from Microbes in Human Welfare, one at a time, marked against the answer key and marking points.Back to the full paper2023 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.