Which of the following is a function of the parasympathetic nervous system?

Which system transmits impulses from the $C.N.S.$?

Which of the following is a function of the parasympathetic nervous system in mammals?

The visceral nervous system $(VNS)$ is a part of the ...... .

$P$ - Contains unmyelinated nerve fibers.
$Q$ - Contains myelinated nerve fibers.
$I$ - Spinal nerves
$II$ - Autonomic neural system
$III$ - Somatic nerve fibers
$IV$ - Cranial nerves
Select the correct option for $P$ and $Q$.
$\quad\quad P$ $\quad$ $\quad$ $Q$

The brain is derived from which embryonic germ layer?