Melatonin is secreted by:

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

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.

Daily rhythms are usually associated with

According to recent knowledge,the pineal body is considered as

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