One of the following statements is not true about thyroxine. This is:(a) Thyroid gland requires iron to synthesize thyroxine(b) It regulates carbohydrate, protein, and fat metabolism(c) Iodine is essential for the synthesis of thyroxine(d) Thyroid gland can enlarge due to lack of thyroxine

(a) Thyroid gland requires iron to synthesise thyroxine.

Statement (a) is not true or incorrect.

Thyroid gland doesn't requires iron to synthesise thyroxine, rather Iodine is required for the synthesis of thyroxine hormone by the thyroid gland.