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

The amino acid tryptophan is the precursor for the synthesis of

Which hormone is secreted more in dark conditions?

$P$ is a small,round,reddish structure located on the dorsal side of the forebrain. It contains a stalk and releases a hormone $Q$ which controls the diurnal rhythm of the body. $P$ and $Q$ are

Which of the following endocrine glands acts as a biological clock and a neurosecretory transducer?

The function of the pineal body is to