Assertion `:-` An increase in body fluid volume activate osmoreceptors , which stimulate the hypothelamus to release ADH.
Reason `:-` ADH facilitates water reabsorptin from later parts of the tubule.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion .
B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion
C. If Assertion is True but the Reason is False.
D. If both Assertion & Reason are false.

Answer

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

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "An increase in body fluid volume activates osmoreceptors, which stimulate the hypothalamus to release ADH."
- Osmoreceptors are sensitive to changes in osmolarity (concentration of solutes) in the blood, not directly to the volume of body fluids. An increase in body fluid volume typically leads to a decrease in osmolarity, which would not activate osmoreceptors to release ADH.

2. **Evaluating the Assertion**:
- Since an increase in body fluid volume would actually decrease osmolarity, the assertion is incorrect. The hypothalamus releases ADH in response to increased osmolarity (not increased fluid volume).

3. **Understanding the Reason**:
- The reason states that "ADH facilitates water reabsorption from later parts of the tubule."
- This statement is true. ADH (Antidiuretic Hormone) acts on the kidneys, specifically on the collecting ducts, to promote water reabsorption, thereby concentrating the urine and reducing water loss.

4. **Evaluating the Reason**:
- Since the reason is true and accurately describes the function of ADH, we can confirm that this part of the statement is correct.

5. **Conclusion**:
- The assertion is false, while the reason is true. Therefore, the correct answer is that the assertion is not a correct explanation of the reason.

### Final Answer:
- Assertion: False
- Reason: True