Skip to content

Study the diagram of a… (Class 12 Biology 2024, Q21)

questionbuddy.in/q/cbse-12-biology-2024-57-1-1-q21-diagram-pyramid-biomass-name-standing

BiologyCBSE Class 12 · Board exam 2024, set 57/1/1 · 2 marks · Very short answer

CBSE Class 12 Biology 2024: question 21

Set in the CBSE Class 12 board exam of 2024, paper 57/1/1, section B, question 21, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q21 · 2 marks · Very short answerCompetency-basedEcosystem

Study the diagram of a pyramid of biomass given below. Name the two standing crops that could be occupying level 'A' and level 'B' in it. Name this type of pyramid and the ecosystem in which it is found.

Figure in the paper: Inverted pyramid of biomass: a wide top bar labelled 'A' with PC (primary consumers) at its right, and a narrower bottom bar labelled 'B' with PP (primary producers) at its right. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 57/1/1.

Hints

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

Hint 1

The producer level is narrower than the consumer level. In which ecosystem does this happen?

Hint 2

In the sea, the producers are tiny floating organisms and the first consumers feed on them.

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. Level A (primary consumers): zooplankton, or small fishes feeding on phytoplankton.

    ½ mark

  2. Level B (primary producers): phytoplankton.

    ½ mark

  3. Type of pyramid: inverted pyramid of biomass, because the small standing crop of phytoplankton supports a larger biomass of consumers.

    ½ mark

  4. Ecosystem: sea (aquatic) ecosystem.

    ½ mark

Answer: A – Zooplankton; B – Phytoplankton; inverted pyramid of biomass; sea (aquatic) ecosystem

Where the marks are

  • A: zooplankton (½ mark)
  • B: phytoplankton (½ mark)
  • Inverted pyramid of biomass (½ mark)
  • Sea/aquatic ecosystem (½ mark)

Revise the chapter

Practise this chapterBoard-style questions from Ecosystem, one at a time, marked against the answer key and marking points.Back to the full paper2024 board paper, set 57/1/1: 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.