ldentify the hormone which performs the following functions -
I. Maintenance of water and electrolyte balance
II. Regulation of BMR
III. Regulation of erythropoiesis

Options

A. Thyroxine
B. Adrenaline
C. ACTH
D. Estrogen

Answer

To identify the hormone that performs the functions of maintaining water and electrolyte balance, regulating BMR (Basal Metabolic Rate), and regulating erythropoiesis, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Functions**:
- **Maintenance of Water and Electrolyte Balance**: This function is crucial for homeostasis in the body. Hormones involved in this process include aldosterone and antidiuretic hormone (ADH).
- **Regulation of BMR**: The Basal Metabolic Rate is primarily regulated by thyroid hormones, particularly thyroxine (T4).
- **Regulation of Erythropoiesis**: Erythropoiesis is the process of red blood cell formation, which is mainly regulated by erythropoietin (EPO), a hormone produced by the kidneys.

2. **Identifying the Hormone**:
- Since we need a single hormone that covers all three functions, we analyze the roles of the hormones mentioned.
- Thyroxine (T4) is known to regulate metabolism, which indirectly influences water and electrolyte balance, and it also plays a role in erythropoiesis by stimulating the production of red blood cells.

3. **Conclusion**:
- The hormone that performs the functions of maintaining water and electrolyte balance, regulating BMR, and regulating erythropoiesis is **Thyroxine (T4)**.

### Final Answer:
The hormone responsible for all three functions is **Thyroxine (T4)**.

---