Asertiion : Inspirations occurs when there is a negative pressure in the lungs with respect to the atmospheric pressure.
Reason : During inspiration, a decrease in pulmonary volume increases the intre-pulmonary pressure than atmospheric pressure which forces the air from outside to moe into the lungs.

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

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that "inspiration occurs when there is a negative pressure in the lungs with respect to atmospheric pressure." This means that for air to flow into the lungs, the pressure inside the lungs (alveolar pressure) must be lower than the pressure outside (atmospheric pressure).

2. **Understanding the Reason:**
- The reason provided is that "during inspiration, a decrease in pulmonary volume increases the inter-pulmonary pressure than atmospheric pressure which forces the air from outside to move into the lungs." This statement is incorrect because during inspiration, the volume of the lungs actually increases, which leads to a decrease in pressure.

3. **Mechanism of Inspiration:**
- When we inhale, the diaphragm contracts and moves downward, while the intercostal muscles (muscles between the ribs) contract and pull the rib cage upward. This action increases the volume of the thoracic cavity.

4. **Pressure Changes:**
- As the thoracic cavity increases in volume, the pressure inside the lungs (pulmonary pressure) decreases. This decrease in pressure creates a negative pressure relative to the atmospheric pressure outside the body.

5. **Airflow into the Lungs:**
- Because the pressure inside the lungs is now lower than the atmospheric pressure, air flows into the lungs until the pressures equalize.

6. **Conclusion:**
- Therefore, the assertion is correct: inspiration does occur when there is negative pressure in the lungs relative to atmospheric pressure. However, the reason is incorrect because it states that a decrease in pulmonary volume increases inter-pulmonary pressure, which is not true; an increase in volume leads to a decrease in pressure.

**Final Answer:**
- The assertion is true, while the reason is false.

---