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(a) Why is it important to… (Class 10 Science 2023, Q22)

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

CBSE Class 10 Science 2023: question 22

Set in the CBSE Class 10 board exam of 2023, paper 31/2/1, section B, question 22, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q22 · 2 marks · Very short answerLife Processes

(a) Why is it important to prevent oxygenated and deoxygenated blood from mixing in birds and mammals ?
(b) Which animals can tolerate some mixing of the oxygenated and deoxygenated blood streams ? On what factor does the body temperature of these animals depend ?

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/2/1.

Hints

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

Hint 1

Birds and mammals keep a constant body temperature. What does that need a lot of?

Hint 2

Think of animals with a three-chambered heart.

Hint 3

Do frogs and lizards control their own body temperature, or does something outside decide it?

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. (a) Birds and mammals are warm-blooded and use a lot of energy to keep their body temperature constant. Keeping oxygenated and deoxygenated blood separate gives a highly efficient supply of oxygen to the body, which meets this high energy demand.

    1 mark

  2. (b) Amphibians (e.g. frogs) and many reptiles can tolerate some mixing of the two blood streams.

    ½ mark

  3. (b) Their body temperature depends on the temperature of the surrounding environment, since they are cold-blooded.

    ½ mark

Answer: (a) Separation gives an efficient oxygen supply for the high energy needed to maintain body temperature. (b) Amphibians/reptiles; body temperature depends on environmental temperature.

Where the marks are

  • Links separation of blood to an efficient oxygen supply for the high energy need of maintaining body temperature (1 mark)
  • Names amphibians or reptiles (½ mark)
  • States that their body temperature depends on the temperature of the environment (½ 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 31/2/1: 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.