Arrange the following events in the correct sequence for the regulation of blood sugar level:
$(i)$ Increase in blood sugar level
$(ii)$ Increase in circulating glucagon
$(iii)$ Release of glucose from glycogen
$(iv)$ Decrease in blood sugar level

Consider the following statements about insulin:
$I$. Human insulin is made up of $51$ amino acids arranged in two polypeptide chains.
$II$. The two polypeptide chains are interconnected by two disulphide bridges.
$III$. In mammals,including humans,insulin is synthesized as a pro-hormone,which contains an extra stretch called the $C$-peptide.
$IV$. $C$-peptide is not present in the mature insulin.
Which of the statements given above are correct?

The nervous system and endocrine glands are

Match the name of the hormone in Column-$I$ with its source of secretion in Column-$II$ and its function in Column-$III$.

Column-$I$	Column-$II$ $\&$ Column-$III$
$(a)$ Prolactin	$(m)$ Pituitary gland,$(q)$ Development of lactiferous tubules
$(b)$ Estrogens	$(l)$ Graafian follicle,$(r)$ Secondary sexual characters in females
$(c)$ GnRH	$(n)$ Hypothalamus,$(s)$ Stimulates release of $FSH$
$(d)$ Androgen	$(o)$ Interstitial cells,$(p)$ Secondary sexual characters of males

Which of the following processes occur in animals?

Write short notes on the functions of the following hormones: (Any four)
$(a)$ Parathyroid hormones $(PTH)$
$(b)$ Thyroid hormones
$(c)$ Thymosin
$(d)$ Androgens
$(e)$ Estrogens
$(f)$ Insulin and Glucagon