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Two green plants are kept… (Class 10 Science 2023, Q24)

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ScienceCBSE Class 10 · Board exam 2023, set 31/4/1 · 2 marks · Very short answer

CBSE Class 10 Science 2023: question 24

Set in the CBSE Class 10 board exam of 2023, paper 31/4/1, section B, question 24, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q24 · 2 marks · Very short answerCompetency-basedLife Processes

Two green plants are kept separately in oxygen free containers, one in the dark and other in sunlight. It was observed that plant kept in dark could not survive longer. Give reason for this observation.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/4/1.

Hints

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

Hint 1

What does a plant need oxygen for?

Hint 2

Which process releases oxygen, and which condition does that process require?

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. The plant kept in the dark cannot photosynthesise, so no oxygen is produced inside the oxygen-free container. Without oxygen it cannot carry out aerobic respiration to release energy, so it dies sooner.

    1 mark

  2. The plant kept in sunlight photosynthesises. It uses and water to produce glucose and oxygen. It uses this oxygen for respiration and gets energy, so it survives longer.

    1 mark

Answer: In the dark there is no photosynthesis, so no oxygen is available for respiration. In light, photosynthesis supplies oxygen for respiration.

Where the marks are

  • Dark plant cannot photosynthesise, so it has no oxygen for respiration (1 mark)
  • Plant in light makes oxygen by photosynthesis and uses it for respiration (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 paper2023 board paper, set 31/4/1: 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.