The diurnal rhythms are regulated by . . . . . . .

The organ which was considered vestigial until recently but is now confirmed to be an endocrine gland is:

The pineal body originates from:

"Pinealocytes" are found in which of the following?

Which of the following helps in the maintenance of the normal rhythm of the sleep-wake cycle?

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?