(i) (a) Oestrogen hormone is responsible for the changes noticed in females at puberty. Oestrogen is, therefore, also known as the female hormone. The various changes noticed during puberty are enlargement of the breast, hair growth of hair in armpits, widening of hips and appearance of pubic hair, height growth and the onset of menstruation.

(b) Dwarfism results due to deficiency of growth hormone.

Growth hormone is released by the anterior pituitary gland. Its deficiency or excessive release can cause height disorders like dwarfism and gigantism respectively.

(c) Blood sugar level rises due to deficiency of Insulin hormone. It is a hormone produced by beta cells of pancreatic islets. It keeps a check on the increase in blood sugar level.

(d) Iodine is necessary for the synthesis of Thyroxine hormone.

(e) Parathyroid hormone (PTH) secreted by parathyroid gland controls the metabolism of calcium and phosphorus in human beings.

(ii) Auxin is an example of plant growth hormone. It is found at the growing tips of root and shoot. It helps in apical growth of the plant.

The height of the stem and the length of the roots increases because of auxin.