The autonomic nervous system has control over

The brain is derived from which embryonic germ layer?

$P$ - The nervous system that relays impulses from the $CNS$ to skeletal muscles.
$Q$ - The nervous system that transmits impulses from the $CNS$ to involuntary organs and smooth muscles of the body.
$\quad\quad\quad P \quad\quad Q$

The effect of oxygen deficiency is primarily observed in which organ?

The covering of a bundle of nerves is . . . . . . .

How many pairs of cranial nerves in mammals are purely sensory?