The sodium-potassium exchange pump

A) must re-establish ion concentrations after each action potential.
B) transports sodium ions into the cell during depolarization.
C) transports potassium ions out of the cell during repolarization.
D) moves sodium and potassium in the direction of their chemical gradients.
E) helps re-establish the ion concentrations between action potentials

The correct answer is option E

Explanation:

Sodium/potassium pump is a mechanism that involves the movement of sodium ions (Na+) out of a cell and potassium ions (K+) into a cell, thereby regulating concentration of ions on both sides of a typical cell membrane.

In this situation, the sodium-potassium pump is usually helps in the establishment of the resting potential. The potassium voltage channels normally closes before the membrane potential is brought to a resting level.

In summary, sodium/potassium pump helps to maintain a balance in the system.