"Pinealocytes" are found in which of the following?

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

$I.$ Sleep-wake cycle,$II.$ Body temperature,$III.$ Pigmentation,$IV.$ Metabolism,$V.$ Defence capability. All of the above-mentioned activities are influenced/regulated by:

Suggest a suitable word for the fourth place: Darkening of skin : $MSH$ :: Lightening of skin : .......

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

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