Which of the following statements describes one of the main functions of the sodium-potassium pump?
A) It maintains the necessary ion concentrations needed for future action potentials.
B) It hyperpolarizes the cell after an action potential has occurred.
C) It ensures that the cell reaches 40 mV during action potentials.
D) It pumps three sodium ions into the cell and two potassium ions out of the cell.
Anaswer: A