Saltatory conduction is observed in which of the following?

Which ions enter the cell at the site marked $P$ in the given diagram?

During the resting state of a neural membrane,if diffusion is allowed due to concentration gradients,which ion is allowed to enter the cell?

Assertion: The imbalance in concentration of $Na^+$,$K^+$ and proteins generates resting potential.
Reason: To maintain the unequal distribution of $Na^+$ and $K^+$,the neurons use electrical energy.

What is resting potential? How does the conduction of a nerve impulse take place?

Which of the following statement/s is/are correct with respect to generation and conduction of nerve impulse?
i. The resting potential difference is $-70 \text{ mV}$.
ii. The voltage-gated $Na^{+}$ and $K^{+}$ channels operate together and are self-closing.
iii. At the peak of action potential,the potential difference rises to $+30$ to $+60 \text{ mV}$.
iv. In medullated nerve fibre,the action potential is conducted as a wave of membrane depolarization.
v. The resting potential is maintained by the closure of gated channels of $Na^{+}$ and $K^{+}$.