The proper intake of iodine in diet helps prevent goitre. Iodine is essential for the functioning of whic endocrine gland?

Options

A. Adrenal
B. Thyroid
C. Testis
D. Ovary

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which endocrine gland requires iodine for its proper functioning and how this relates to the prevention of goitre.

2. **Identifying the Endocrine Gland**: The endocrine gland that is essential for iodine is the thyroid gland.

3. **Function of the Thyroid Gland**: The thyroid gland produces hormones, primarily T3 (triiodothyronine) and T4 (thyroxine), which are crucial for regulating metabolism, growth, and development in the body.

4. **Role of Iodine**: Iodine is a vital component in the synthesis of T3 and T4 hormones. Without adequate iodine intake, the thyroid gland cannot produce these hormones effectively.

5. **Consequences of Iodine Deficiency**: A deficiency in iodine can lead to hypothyroidism, a condition where the thyroid gland does not produce enough hormones. This can cause the thyroid gland to enlarge, leading to a condition known as goitre.

6. **Conclusion**: Therefore, the proper intake of iodine in the diet is essential for the functioning of the thyroid gland, and its deficiency can lead to goitre.

### Final Answer:
Iodine is essential for the functioning of the **thyroid gland**.

---