Assertion :- Decreased secretion of growth hormone by anterior pituitary result in stunted growth.
Reason:- Deficiency of Iodine results in deficiency of thyroxine.

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 but 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.

Answer

### Step-by-Step Text Solution:

1. **Understanding the Assertion**: The assertion states that decreased secretion of growth hormone by the anterior pituitary results in stunted growth. This is true because growth hormone (GH) is crucial for normal growth and development. A deficiency in GH can lead to conditions such as dwarfism, which is characterized by stunted growth.

2. **Understanding the Reason**: The reason given is that a deficiency of iodine results in a deficiency of thyroxine. This statement is also true. Iodine is an essential element required for the synthesis of thyroxine (T4), a hormone produced by the thyroid gland. A lack of iodine can lead to hypothyroidism, which is characterized by low levels of thyroxine.

3. **Analyzing the Relationship**: While both the assertion and the reason are true, the reason does not explain the assertion. The assertion pertains to growth hormone and its role in growth, while the reason pertains to thyroid hormone and its role in metabolism. Therefore, the deficiency of iodine and thyroxine does not directly explain the effects of growth hormone deficiency.

4. **Evaluating the Options**:
- Option 1 states that both assertion and reason are true and that the reason is the correct explanation of the assertion. This is incorrect.
- Option 2 states that both assertion and reason are true but the reason is not the correct explanation of the assertion. This is correct.
- Option 3 states that the assertion is true and the reason is false. This is incorrect.
- Option 4 states that both assertion and reason are false. This is incorrect.

5. **Conclusion**: The correct answer is Option 2: Both assertion and reason are true, but the reason is not the correct explanation of the assertion.