Q19
1 markMCQSection A

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.

Life Processes
Transportation in Human Beings

Options

(a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
(b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
(c)Assertion (A) is true, but Reason (R) is false.
(d)Assertion (A) is false, but Reason (R) is true.
Official Answer

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

ventriclesatriathicker wallshigh pressurepumping blood

Marking Scheme

  • 11 Mark for selecting the correct option (d).

Hint

Think about which chambers of the heart have to pump blood over longer distances (like to the lungs or the entire body) and therefore require more muscular force.

Quick Oral Answer

Ventricles have thicker muscular walls than atria because they must pump blood to various organs of the body under high pressure, whereas atria only receive blood and pump it into the ventricles.

Analysis & Explanation

Let us analyze the Assertion and Reason individually:

  • Assertion (A): 'The walls of atria are thicker than those of the ventricles.' This statement is false. Ventricles have much thicker muscular walls than atria because ventricles have to pump blood to various distant organs of the body (such as the lungs and systemic organs) at high pressure, whereas atria only need to receive blood and pump it into the adjacent ventricles.
  • Reason (R): 'Ventricles have to pump blood into various organs at high pressure.' This statement is true.

Since Assertion (A) is false but Reason (R) is true, the correct option is (d).

Common Mistakes

  1. 1Believing that atria have thicker walls because they receive blood first.
  2. 2Confusing the thickness of the left ventricle with the right ventricle, or atria with ventricles in general.

Interesting Facts

The left ventricle wall is about three times thicker than the right ventricle wall because it must generate enough pressure to pump blood throughout the entire systemic circulation of the body.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2023?

This question carries 1 mark in the CBSE Class 10 Science 2023 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Life Processes" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Transportation in Human Beings" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2023 paper?

This is a MCQ question from Section A in the CBSE Class 10 Science 2023 paper.