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How many chambers are… (Class 10 Science SQP 2025-26, Q11A)

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ScienceCBSE Class 10 · Sample paper, session 2025-26 · 2 marks · Very short answer

CBSE Class 10 Science sample paper 2025-26: question 11(A)

From the official CBSE sample question paper for 2025-26, section A, question 11(A), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q11(A) · 2 marks · Very short answerLife Processes

How many chambers are there in the heart of the following organisms? How is mixing of oxygenated and deoxygenated blood prevented in their body?
(i) Fishes
(ii) Humans

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2025-26.

Hints

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

Hint 1

Count the atria and ventricles in each heart.

Hint 2

In fish, does oxygenated blood ever come back into the heart? In humans, what divides the heart into left and right?

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) Fishes: 2 chambers (one atrium, one ventricle). The heart receives only deoxygenated blood and pumps it to the gills. There it is oxygenated and goes straight to the body tissues, without returning to the heart. Oxygenated blood never enters the heart, so no mixing occurs. This is single circulation.

    1 mark

  2. (ii) Humans: 4 chambers (2 atria, 2 ventricles). A wall called the septum separates the right side, which carries deoxygenated blood, from the left side, which carries oxygenated blood. This keeps the two kinds of blood apart. This is double circulation.

    1 mark

Answer: (i) Fish: 2 chambers; blood goes heart → gills → body, so the heart holds only deoxygenated blood. (ii) Humans: 4 chambers; a septum separates the right and left sides.

Where the marks are

  • Fish: 2 chambers and the reason there is no mixing (blood oxygenated in gills goes directly to the body) (1 mark)
  • Human: 4 chambers and the septum separating oxygenated and deoxygenated blood (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 paperSample paper 2025-26: 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.