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The opening and closing of… (Class 10 Science 2025, Q6)

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ScienceCBSE Class 10 · Board exam 2025, set 31/2/1 · 1 mark · MCQ

CBSE Class 10 Science 2025: question 6

Set in the CBSE Class 10 board exam of 2025, paper 31/2/1, section A, question 6, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q6 · 1 mark · MCQLife Processes

The opening and closing of stomata is regulated by :

  1. (A) concentration in stomata
  2. (B)Temperature in guard cells
  3. (C) concentration in stomata
  4. (D)Amount of water in guard cells

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/2/1.

Hints

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

Hint 1

Think about what makes guard cells swell or shrink.

Hint 2

It is a change in their turgidity.

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. Each stoma is surrounded by two guard cells.

  2. When water flows into the guard cells, they swell and the pore opens. When they lose water, they shrink and the pore closes.

  3. So stomata are regulated by the amount of water in the guard cells: (D).

    1 mark

Answer: (D) Amount of water in guard cells

Where the marks are

  • Selects amount of water in guard cells, option (D) (1 mark)

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 paper2025 board paper, set 31/2/1: 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.