Answer: Three sodium ions.
- A Three sodium ions
- B Two sodium ions
- C One sodium ion
- D No sodium ions
Correct answer: A. Three sodium ions
Explanation: The Na<sup>+</sup>/K<sup>+</sup> pump exports 3 Na<sup>+</sup> for every 2 K<sup>+</sup> it imports, maintaining the resting potential.
Structure of a neuron. Image: LadyofHats (Mariana Ruiz), Public Domain, via Wikimedia Commons.
Concept context
Brain, spinal cord, neurons, reflex arcs, and sense organs.