The rate of rise of action potential and its amplitude are determined by the concentration of

Assertion $(A)$: The axonal membrane of the neuron is more permeable to sodium ion $(Na^+)$ and nearly impermeable to potassium $(K^+)$.
Reason $(R)$: In a resting state,a neuron does not conduct any impulse.

Select the correct sequence of statements regarding the conduction of a nerve impulse and select the correct option given below.
$i.$ Rapid influx of $Na^{+}$ inside the axon.
$ii.$ $Na^{+}$ gates are closed and $K^{+}$ gates open after the refractory period.
$iii.$ Intracellular fluid is electronegative and the potential difference is $-70 \ mV$.
$iv.$ Extracellular fluid becomes electronegative.
$v.$ Disturbance to the resting potential.

When a neuron is not conducting any impulse,the axonal membrane is comparatively more permeable to $K^+$ ions and nearly impermeable to $Na^+$ ions.

In the resting stage of a neuron,the concentration gradient allows the diffusion of which ions?

During the conduction of a nerve impulse,the action potential results from the movement of