Assertion : At the lung alveoli level , blood releases carbon dioxide.
Reason : Oxy Hb formed at the lung alveoli level acts as a weak acid which favours release of `CO_(2)` .

Options

A. If both Assertion and Reason are true and Reason is a correct explaintion of Assertion .
B. If both assertion and Reason are ture Reason are ture Reason is not a correct explanation of Assertion .
C. If Assertion is ture but Reason is false .
D. If both assertion and Reason are false .

Answer

To solve the question regarding the assertion and reason about gas exchange at the lung alveoli level, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "At the lung alveoli level, blood releases carbon dioxide."
- This is true because during the process of gas exchange in the alveoli, carbon dioxide (CO₂) diffuses from the blood into the alveoli to be exhaled.

2. **Understanding the Reason**:
- The reason states that "Oxy Hb formed at the lung alveoli level acts as a weak acid which favors the release of CO₂."
- This statement is misleading. While it is true that oxyhemoglobin (Oxy Hb) forms when oxygen binds to hemoglobin in the presence of high oxygen concentration in the alveoli, it does not act as a weak acid in a way that promotes the release of CO₂.

3. **Analyzing the Relationship**:
- The assertion is correct, but the reason is incorrect. Oxyhemoglobin does not favor the release of CO₂ by acting as a weak acid. Instead, the release of CO₂ is facilitated by the conversion of bicarbonate ions back to CO₂ in the presence of protons, which is not accurately described in the reason.

4. **Conclusion**:
- Since the assertion is true and the reason is false, the correct answer to the question is that the assertion is true but the reason is false.

### Final Answer:
- The correct option is: "Assertion is true but reason is false."

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