Complete the following analogy-based questions:
$1$. Hyperglycemia : Diabetes Mellitus :: Beta cells : ....
$2$. Excess Growth Hormone : Gigantism :: Low secretion : .......
$3$. Pineal gland : Melatonin :: Somatostatin : .....

(A) $1$. Hyperglycemia is caused by a deficiency of insulin,which is secreted by the Beta cells of the Islets of Langerhans. Therefore,the analogy relates the condition to the source of the hormone. The answer is Insulin.
$2$. Excess growth hormone leads to Gigantism. Conversely,low secretion of growth hormone during childhood leads to Dwarfism (or stunted growth).
$3$. The Pineal gland secretes Melatonin. Somatostatin is a hormone secreted by the Hypothalamus (it inhibits the release of growth hormone from the anterior pituitary).