Assertion : Thyroxine shows calorigenic effect.
Reason : Thyroxine increases catabolism, produces energy and increases body temperature.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1).
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion then mark (2).
C. If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statements, then mark (4)

Answer

### Step-by-Step Text Solution:

1. **Understanding the Assertion**: The assertion states that "Thyroxine shows calorigenic effect." This means that thyroxine, a hormone produced by the thyroid gland, has an effect on the body's metabolism that leads to an increase in heat production.

2. **Understanding the Reason**: The reason provided is that "Thyroxine increases catabolism, produces energy, and increases body temperature." This implies that thyroxine enhances metabolic processes that break down substances in the body, leading to energy production and a rise in body temperature.

3. **Role of Thyroxine**: Thyroxine is known to increase the Basal Metabolic Rate (BMR). This means that it boosts the rate at which the body uses energy at rest. It achieves this by promoting catabolic processes.

4. **Calorigenic Effect Explained**: The calorigenic effect refers to the body's ability to generate heat through metabolic processes. Thyroxine contributes to this by:
- **Glucogenesis**: The breakdown of glucose for energy.
- **Lipolysis**: The breakdown of fats for energy.
- **Proteolysis**: The breakdown of proteins for energy, though this occurs after the breakdown of glucose and fats.

5. **Conclusion**: Since the assertion is true (thyroxine does show a calorigenic effect) and the reason is also true (thyroxine increases catabolism, produces energy, and raises body temperature), we can conclude that the reason correctly explains the assertion.

6. **Final Answer**: Both the assertion and reason are true, and the reason is the correct explanation for the assertion.