a) - iii

Deficiency of thyroxine hormone causes goiter. Iodine is responsible for secretion of thyroxine hormone. So lack of iodine in diet would cause goiter which is marked as a swelling in the neck.

b) - iv

Growth hormone is secreted by the pituitary gland and it's under secretion causes dwarfism. In this condition, the person cannot grows well leading to stunted growth.

c) - ii

Insulin is secreted by the pancreas which regulates blood sugar level in our body. So a deficiency of this hormone causes diabetes where more sugar level is found in blood.

d) - i

Adrenal hormone deficiency leads to a salt imbalance in our body. A hormone named aldosterone regulates sodium potassium levels in our blood so its deficiency leads to an imbalance of these salt levels.