Assertion : The abdominal muscles are primarily involved in generating pressure gradient between the lungs and the atmosphere.
Reason : The strength of inspiration and expiration can be increased by abdiminal muscles in diaphragm and intercostal muscles.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true and reason is not the correct explanation of assertion
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "The abdominal muscles are primarily involved in generating pressure gradient between the lungs and the atmosphere."
- The primary muscles responsible for generating the pressure gradient during breathing are actually the diaphragm and the intercostal muscles, not the abdominal muscles. Therefore, this assertion is incorrect.

2. **Understanding the Reason**:
- The reason states that "The strength of inspiration and expiration can be increased by abdominal muscles in diaphragm and intercostal muscles."
- While it is true that abdominal muscles can assist in expiration (particularly during forceful breathing), the diaphragm and intercostal muscles are the primary muscles involved in both inspiration and expiration. The statement is misleading because it implies that abdominal muscles are involved in both processes equally, which is not accurate. Hence, this reason is also incorrect.

3. **Conclusion**:
- Since both the assertion and the reason are incorrect, we can conclude that the correct answer is that both the assertion and the reason are false.

### Final Answer:
Both the assertion and the reason are incorrect.

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