Which of the following elements is required by the thyroid gland to make thyroxine hormone?
Iodine
The single most important use of the element iodine in animal biology - which of course includes human biology, is for the formation of two hormones in the thyroid gland (which is an endocrine gland). The hormones are thyroxine (sometimes called T4) and triiodothyronine (sometimes called T3).