(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

(i) The formation of Thyroxine `(T_4)` and Triiodothyronine requires iodine. If there is an inadequate supply of iodine in our diet it leads to enlargement o thyroid gland called goitre.
(ii) The importance of rainwater harvesting is as follows :
(i) Overcome the rapid depletion of ground water level.
(ii) To meet the increased demand of water.
(iii) Reduces flood and soil erosion.
(iv) Water stored in ground is not contarninated by human and animal wastes and hence can be used for drinking purposes.
(iii) The first fluid which is produced from the mammary gland after child birth is called colostrums . Milk production from alveoli of mammary gland is stimulated by prolactin secreted from anterior pituitary.