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Give three reasons as… (Class 12 Biology SQP 2023-24, Q28)

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BiologyCBSE Class 12 · Sample paper, session 2023-24 · 3 marks · Short answer

CBSE Class 12 Biology sample paper 2023-24: question 28

From the official CBSE sample question paper for 2023-24, section C, question 28, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q28 · 3 marks · Short answerBiodiversity and Conservation

Give three reasons as to why the prokaryotes are not given any figures for their diversity by the ecologists.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2023-24.

Hints

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

Hint 1

Think about how a new species is normally identified and described.

Hint 2

Can every bacterium be grown on a culture plate?

Hint 3

What do molecular studies suggest about the total number of microbial species?

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. Classifying and identifying the huge diversity of microbes is very difficult. Conventional taxonomic methods are not suitable for this.

    1 mark

  2. Many microorganisms cannot be cultured under laboratory conditions, so they cannot be studied and counted.

    1 mark

  3. Biochemical and molecular techniques suggest that prokaryotic species could run into millions or billions, living in very diverse habitats (air, water, soil, extreme environments). More advanced techniques are still needed to estimate this diversity reliably.

    1 mark

Answer: (1) Classification/identification of microbes is very difficult; (2) many cannot be cultured in the lab; (3) molecular estimates suggest an enormous (millions to billions) diversity that current methods cannot count.

Where the marks are

  • Difficulty in identification/classification by conventional methods (1 mark)
  • Many microbes cannot be cultured in the laboratory (1 mark)
  • Enormous diversity in varied habitats, estimated only by molecular techniques (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Biodiversity and Conservation, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2023-24: 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.