Intercellular communication in humans takes place by:

Given below are two statements. Read them and choose the correct pair below.
Statement-$I$: Melatonin regulates the sleep-wake cycle,body temperature,metabolism,and reproductive cycles.
Statement-$II$: Thyroxin increases the action of neurotransmitters and supports the $RBC$ production.

Which of the following organ systems jointly coordinate and integrate all the activities of the body organs?

Which of the following matches is correct?

Match the hormones given in Column $I$ with their source gland in Column $II$.

Column $I$	Column $II$
$i$. Oxytocin	$a$. Adrenal medulla
$ii$. Melatonin	$b$. Thyroid gland
$iii$. Catecholamines	$c$. Pineal gland
$iv$. Calcitonin	$d$. Hypothalamus

Choose the correct option from below:

There are many endocrine glands in the human body. Name the glands which are absent in males and the ones absent in females.