Assertion : Secretion of ADH is controlled by osmotic pressure of blood.
Reason : Changes in osmotic pressure are noted by osmoreceptors present in the hypothalamus.

Options

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

Answer

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

### Step 1: Understand the Assertion
The assertion states that "Secretion of ADH is controlled by osmotic pressure of blood."
- **Explanation**: Antidiuretic hormone (ADH), also known as vasopressin, is released from the posterior pituitary gland in response to changes in the osmotic pressure of the blood. When the osmotic pressure increases (indicating dehydration or high solute concentration), ADH secretion increases to promote water reabsorption in the kidneys, thus diluting the blood and lowering osmotic pressure.

### Step 2: Understand the Reason
The reason states that "Changes in osmotic pressure are noted by osmoreceptors present in the hypothalamus."
- **Explanation**: Osmoreceptors are specialized neurons located in the hypothalamus that detect changes in the osmotic pressure of the blood. When osmotic pressure rises, these osmoreceptors activate and signal the hypothalamus to release more ADH from the posterior pituitary.

### Step 3: Analyze the Relationship
Now, we need to determine if the reason correctly explains the assertion.
- The assertion is true as ADH secretion is indeed controlled by osmotic pressure.
- The reason is also true as osmoreceptors in the hypothalamus do detect changes in osmotic pressure.

### Conclusion
Since both the assertion and reason are true, and the reason correctly explains the assertion, the correct answer is:
1. Both Assertion and Reason are True and Reason is a Correct Explanation of Assertion.