(i) Which hormone requires iodine for its formation ? What will happen if intake of iodine in our diet is low ?
(ii) What is the importance of raivater harvesting ?
(iii) What is colosturm ? How is milk production hormonally regulated ?

Explanation

The hormones secreted by the thyroid gland are:
(a) Triiodothyronine `(T_3)`
(b) Tetraiodothyronine or Thyroxin `(T_4)` , which need an amino acid tyrosine and lodine for its formation. If the intake of lodine in our diet is low or due to the inadequate supply of iodine in our diet leads to the enlargement of thyroid gland, which protrudes, as swelling in the neck and is called as goitre.