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Science — CBSE Class 10 board question

Q1. [1]
Assertion (A) : The walls of atria are thicker than those of the ventricles. Reason (R) : Ventricles have to pump blood into various organs at high pressure.
  1. (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  2. (b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
  3. (c) Assertion (A) is true, but Reason (R) is false.
  4. (d) Assertion (A) is false, but Reason (R) is true.
Previously asked in CBSE board exam
2023 31/5/1 Q19
Generated by claude-sonnet-4-6 · 2026-06-11 09:49 · grounding rag
Model Answer

(d) Assertion (A) is false, but Reason (R) is true.

The Assertion is false — ventricles have thicker walls than atria. The Reason is true — ventricles pump blood to various organs at high pressure.

Source: Chapter 5, Section 5.4.1 (Transportation in Human Beings)

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Explanation

The textbook clearly states: "ventricles have to pump blood into various organs, they have thicker muscular walls than the atria do." So the Assertion incorrectly swaps the relationship — it's the ventricles that are thick-walled, not the atria. The Reason correctly explains why ventricles need thick walls. Hence option (d) is correct.

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