Questions: Identify the events that occurs toward the end of the repolarization phase The Na+ activation gates close and the inactivation gates open. Both the Na+ activation and inactivation gates open. The Na+ activation gates open and the inactivation gates close.

The answer is the first one: The Na+ activation gates close and the inactivation gates open.

Explanation for each option:

1. The Na+ activation gates close and the inactivation gates open.

   • This is correct. Toward the end of the repolarization phase, the Na+ channels reset by closing the activation gates and opening the inactivation gates, preparing the neuron for the next action potential.

2. Both the Na+ activation and inactivation gates open.

   • This is incorrect. If both gates were open, Na+ ions would continue to flow into the cell, which would not allow for repolarization to occur.

3. The Na+ activation gates open and the inactivation gates close.

   • This is incorrect. This describes the state of the Na+ channels during the depolarization phase, not the repolarization phase.

Summary: Toward the end of the repolarization phase, the Na+ activation gates close and the inactivation gates open, resetting the Na+ channels for the next action potential.