Question

the following hormones required iodine for its synthesis

Answer 1

thyroxine is the hormone required for iodine synthesis. Deficiency of this hormone causes goitre

Answer 2

Thyroid gland requires iodine for the secretion of the hormone Thyroxine. Thyroxine is also essential for organisms like frogs to do metamorphosis, and for that too, water in which the tadpoles grow need to have sufficient iodine.