Respuesta :
Answer:
A. Ions are moved against the concentration gradient.
Explanation:
Active transport is a process of transport of substances that moves the substances against their concentration gradient. This means that a substance is being moved from the region of its lower concentration to the region of its higher concentration.
To move the substances against their concentration gradients, cells spend metabolic energy. Therefore, active transport always requires energy to move the substances. Since sodium-potassium pump uses energy to move sodium and potassium ions, it is moving these ions against the concentration gradient.