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Read the following passage… (Class 10 Science 2026, Q15a)

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ScienceCBSE Class 10 · Board exam 2026, set 31/3/1 · 4 marks · Case-based

CBSE Class 10 Science 2026: question 15(a)

Set in the CBSE Class 10 board exam of 2026, paper 31/3/1, section A, question 15(a), for 4 marks. Try it first; the hints and our step-by-step solution are below.

Q15(a) · 4 marks · Case-basedCompetency-basedLife Processes

Read the following passage and answer the questions that follow :

Not all plants carry out photosynthesis by the same mechanism. In most plants, it depends directly on gaseous carbon dioxide that diffuses into the leaf. However, some plants can store carbon dioxide in the vacuole of the leaf cells as part of a complex carbon compound. This compound is transported to the chloroplast and releases carbon dioxide when required for photosynthesis. This special mechanism is believed to have evolved as an adaptation in such plants which do not open stomata during the daytime to conserve water for survival in dry conditions (desert conditions).

  1. (i)

    Which process in these plants is minimised to help the plants survive in dry conditions ?

    0 marks
  2. (ii)

    Which part of the leaf is responsible for exchange of gases during photosynthesis ?

    0 marks

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/3/1.

Hints

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

Hint 1

The passage says these plants keep stomata shut in the daytime. What is lost through open stomata?

Hint 2

Gases enter and leave a leaf through tiny pores. Name 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. (i) Transpiration, the loss of water as vapour, is minimised. These plants keep their stomata closed during the day, which cuts water loss so they can survive in dry conditions.

    2 marks

  2. (ii) The stomata, the tiny pores on the leaf surface, are responsible for exchange of gases ( in, out) during photosynthesis.

    2 marks

Answer: (i) Transpiration (water loss through stomata) is minimised; (ii) Stomata

Where the marks are

  • Identifies transpiration / loss of water through stomata during the day as minimised (2 marks)
  • Names stomata (2 marks)

Revise the chapter

  • Chapter: Life Processes (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Life Processes, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 31/3/1: 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.