Trembling,depression,fear,and phobia are signs of:

One of the examples of the action of the autonomous nervous system is

Which of the following cranial nerves are classified as mixed nerves?

$I.$ The endocrine system provides chemical integration through hormones.
$II.$ The neural system provides an organized network of point-to-point connections for quick coordination.
$III.$ The neural organization is very complex in lower invertebrates.
$IV.$ The human neural system includes $CNS$ and $PNS$.
Select the correct statements.

Explain the following:
$(a)$ Role of $Na ^{+}$ in the generation of action potential
$(b)$ Mechanism of generation of light-induced impulse in the retina.
$(c)$ Mechanism through which a sound produces a nerve impulse in the inner ear.

Identify the location and function of the following structures:
$(1)$ Cone cells
$(2)$ Ear ossicles