Which statement is not true about thyroxin?

The correct option is A

Iron is essential for the synthesis of thyroxin.

The correct option is A.

Explanation of the correct option:

1. The thyroid is the largest endocrine gland attached to track below the larynx.
2. It is an H-shaped gland.
3. Thyroxin hormone, along with calcitonin, is released by the thyroid gland.
4. The synthesis of thyroxine does not require an iron element.

Explanation of the incorrect options:

Option A:

• The function of the thyroxin hormone is used to regulate the metabolism of carbohydrate proteins and fats, so this statement is true.

Option B:

• Iodine is an essential element for synthesizing the thyroxine hormone, so this statement is also true.

Option D:

• The thyroid gland releases thyroxine. It is also known as the thyroid hormone. Hence, this statement is also true.

Final Answer: The statement which is not true about thyroxine is that its production requires iron.