Where is postganglionic sympathetic cholinergic innervation found?

Distinguish between (Any four):
$(a)$ Afferent neurons and Efferent neurons
$(b)$ Impulse conduction in a myelinated nerve fibre and an unmyelinated nerve fibre
$(c)$ Aqueous humour and vitreous humour
$(d)$ Blind spot and Yellow spot
$(e)$ Cranial nerves and Spinal nerves

$ECT$ is

Which of the following is an example of the action of the autonomous nervous system?

Choose the correct option:
$(1)$ The saccule and utricle contain a projecting ridge called the $ \text{crista} / \text{macula} $.
$(2)$ The space between the cornea and the lens is called the $ \text{aqueous chamber} / \text{vitreous chamber} $.

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.