Melatonin is secreted by the . . . . . . .

George comes on a vacation to India from the $U.S.$ The long journey disturbs his biological system and he suffers from jet lag. What is the cause of his discomfort?

Select the correct match regarding the source and function of the hormone.

From which one of the following,the melatonin is derived?

The pineal gland secretes which hormones?
$I. Serotonin$ $II. ACTH$ $III. MSH$ $IV. PRL$ $V. Melatonin$ $VI. FSH$
The correct option is:

Identify the correct gland on the basis of the following characteristics:
$(I)$ It is located on the dorsal side of the forebrain.
$(II)$ It plays a very important role in the regulation of the $24$-hour rhythm of our body.
$(III)$ It helps in maintaining body temperature.
$(IV)$ Its hormone influences metabolism as well as defense capability.