The main function of thyroid gland Is to control :

Options

A. Growth
B. Reproduction
C. Secondary sexual characters
D. Basal metabolic rate

Answer

**Step-by-Step Solution:**

1. **Identify the Gland:** The thyroid gland is an endocrine gland located in the neck, composed of two lobes situated on either side of the trachea.

2. **Recognize the Hormones Produced:** The thyroid gland primarily produces two hormones:
- Tetraiodothyronine (T4)
- Triiodothyronine (T3)

3. **Understand the Main Function:** The primary function of the thyroid gland is to regulate the basal metabolic rate (BMR) of the body. This means it controls how quickly the body uses energy and how it metabolizes carbohydrates, fats, and proteins.

4. **Other Functions:** While the thyroid gland does play a role in growth and development, these functions are more directly regulated by other hormones (like growth hormone from the pituitary gland). The thyroid hormones also influence the metabolism of red blood cells and the regulation of calcium levels through the hormone calcitonin.

5. **Conclusion:** Therefore, the main function of the thyroid gland is to control the basal metabolic rate (BMR).

**Final Answer:** The main function of the thyroid gland is to control the basal metabolic rate (BMR).

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