A: Normal expiration during quiet breathing, unlike
inspiration, is a passive process because on
muscular contractions are involved.
R: Normal expiration results from the elastic recoil
of the chest wall and lungs.

Options

A. If both Assertion & Reason are true and the
reason is the correct explanation of the
assertion, then mark (1)
B. If both Assertion & Reason are trye but the
reason is not the correct explanation of the
assertion , then mark (2)
C. If Assertion is true statement but Reason is
fakse, then mark (3)
D. If both Assertion and Reason are false
statements, then mark (4)

Answer

To analyze the assertion and reason provided in the question, we can break down the concepts step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Normal expiration during quiet breathing, unlike inspiration, is a passive process because no muscular contractions are involved."
- In normal expiration, the process does not require active muscular effort. Instead, it occurs as a result of the relaxation of the diaphragm and intercostal muscles after they have contracted during inspiration.

2. **Understanding the Reason (R)**:
- The reason states that "Normal expiration results from the elastic recoil of the chest wall and lungs."
- The lungs and chest wall have elastic properties. When the diaphragm and intercostal muscles relax, the elastic recoil of the lungs causes them to return to their original shape, pushing air out of the lungs.

3. **Evaluating the Truth of the Assertion**:
- The assertion is true because normal expiration does not involve active muscular contractions. It is a passive process that occurs due to the relaxation of the muscles involved in inspiration.

4. **Evaluating the Truth of the Reason**:
- The reason is also true because normal expiration is indeed facilitated by the elastic recoil of the lungs and chest wall. This recoil is what drives air out of the lungs during expiration.

5. **Determining the Relationship**:
- Since both the assertion and the reason are true, and the reason accurately explains the assertion, we conclude that the correct answer is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.

### Final Conclusion:
Both the assertion and reason are true, and the reason is the correct explanation of the assertion.

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