What is the role of the sodium-potassium pump in cells?

• A. It uses glucose to transport sodium and potassium across the membrane.
• B. It facilitates the passive diffusion of sodium and potassium across the membrane.
• C. It maintains electrochemical gradients by pumping sodium out and potassium into the cell.
• D. It blocks the movement of sodium and potassium across the membrane.

Answer: (C)