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Answer the following. (Class 10 Science 2023, Q29b)

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ScienceCBSE Class 10 · Board exam 2023, set 31/1/1 · 3 marks · Short answer

CBSE Class 10 Science 2023: question 29(b)

Set in the CBSE Class 10 board exam of 2023, paper 31/1/1, section C, question 29(b), for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q29(b) · 3 marks · Short answerCompetency-basedLife Processes

Answer the following.

  1. (i)

    What is the internal energy reserve in plants and animals ?

    0 marks
  2. (ii)

    How desert plants perform photosynthesis if their stomata remain closed during the day ?

    0 marks

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

Hints

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

Hint 1

Plants store carbohydrate as one polysaccharide and animals as another. The animal one is stored in the liver and muscles.

Hint 2

If the stomata cannot open in the day, when could CO₂ be collected and stored?

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) In plants, food is stored as the internal energy reserve starch.

    1 mark

  2. In animals (including humans), the internal energy reserve is glycogen.

    1 mark

  3. (ii) Desert plants keep their stomata open at night and take in . They convert it into an intermediate compound (an acid) and store it. During the day, the stomata stay closed to reduce water loss. Chlorophyll absorbs sunlight, and this energy is used to release from the stored intermediate. This is then used to make carbohydrates.

    1 mark

Answer: (i) Starch in plants, glycogen in animals; (ii) they take in CO₂ at night and store it as an intermediate, which is used in the day with light energy absorbed by chlorophyll.

Where the marks are

  • Starch in plants (1 mark)
  • Glycogen in animals (1 mark)
  • CO₂ taken in at night, stored as an intermediate and used in the day with light energy (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 31/1/1: 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.