________ has an important role in the development of immune system by maturation of T lymphocytes.

Options

A. Thyroxine
B. Thymosin
C. Aldosterone
D. Parathormone

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks which substance plays a crucial role in the development of the immune system, specifically in the maturation of T lymphocytes.

2. **Identify the Options**: The options provided are Thyroxin, Thymosine, Aldosterone, and Parathormone.

3. **Analyze Each Option**:
- **Thyroxin**: This hormone is produced by the thyroid gland and primarily regulates the basal metabolic rate of the body. It does not play a direct role in the immune system or T lymphocyte maturation.
- **Thymosine**: This hormone is produced by the thymus gland and is directly involved in the immune system. It is crucial for the maturation of T lymphocytes and stimulates the production of T-cells, which are essential for immune responses.
- **Aldosterone**: This hormone is produced by the adrenal gland and is mainly responsible for regulating sodium and potassium levels in the body. It does not have a role in the immune system.
- **Parathormone**: This hormone is produced by the parathyroid gland and regulates calcium levels in the blood. It does not influence the immune system or T lymphocyte maturation.

4. **Select the Correct Answer**: Based on the analysis, Thymosine is the hormone that plays an important role in the development of the immune system by facilitating the maturation of T lymphocytes.

5. **Final Answer**: The correct answer is **Thymosine**.

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