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The population… (Class 12 Biology SQP 2025-26, Q28)

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BiologyCBSE Class 12 · Sample paper, session 2025-26 · 3 marks · Short answer

CBSE Class 12 Biology sample paper 2025-26: question 28

From the official CBSE sample question paper for 2025-26, section C, question 28, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q28 · 3 marks · Short answerCompetency-basedOrganisms and Populations

The population pyramids of Japan for the years 1950, 2007 and on the basis of the estimated value for 2050 have been shown below to answer the questions that follow:
A. Comment upon the growth status of the population on the basis of shape of the age pyramids.
B. What insights can you gain about their population dynamics?

(For visually impaired students: The population pyramids of Japan for the years 1950, 2007 and on the basis of the estimated value for 2050 have broad-based, inverted bell and urn shape, respectively. Answer the following questions: A. Comment upon the growth status of the population on the basis of shape of the age pyramids. B. What insights can you gain about their population dynamics?)

Figure in the paper: Three age-sex pyramids titled 'Changes in the Population Pyramid' for 1950, 2007, 2050 (males left, females right, age 0-90, millions). 1950: broad base; 65 and over 4.9%, 15-64 59.6%, 0-14 35.4%. 2007: inverted bell; 65 and over 21.5%, 15-64 65.0%, 0-14 13.5%. 2050: urn/inverted shape; 65 and over 39.6%, 15-64 51.8%, 0-14 8.6%. See it in the official paper.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2025-26.

Hints

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

Hint 1

Relate each shape to one of three growth types: expanding, stable, declining.

Hint 2

Look at how the 0–14 share changes from 1950 to 2050.

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. 1950 – Expanding (growing) population. The broad base (0–14 years = 35.4%) shows a large share of young people, so the birth rate is high and the population is growing.

    1 mark

  2. 2007 – Stable population. The base has narrowed (0–14 years = 13.5%) and pre-reproductive and reproductive age groups are nearly balanced (15–64 years = 65%). The bell-like shape shows the population was nearly static, with falling birth rate and rising elderly share (21.5%).

    1 mark

  3. 2050 – Declining population. The urn-shaped pyramid (0–14 years = 8.6%, 65+ = 39.6%) shows very low birth rates and a growing elderly population, so the population will shrink. Insight: Japan is moving from high to low birth rate with rising life expectancy. This means an ageing population, a shrinking workforce and more dependence on fewer working-age people.

    1 mark

Answer: 1950 – expanding (broad base, high birth rate); 2007 – stable (bell shape); 2050 – declining (urn shape, low birth rate, ageing population).

Where the marks are

  • 1950 expanding – broad base, high birth rate (1 mark)
  • 2007 stable – nearly equal pre-reproductive and reproductive groups (1 mark)
  • 2050 declining – urn shape, low birth rate, more elderly (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 paperSample paper 2025-26: 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.