For a neuron to return to rest the axon must alose a negative charge blose a positive charge cgain a negative charge dgain more sodium

The correct answer is c) gain a negative charge.

Here's the step by step explanation:

1. When a neuron is at rest, it maintains a balance of ions, with more positive ions outside the neuron and more negative ions inside. This creates a negative resting potential.

2. When a neuron fires, it undergoes a process called depolarization. Sodium ions rush into the neuron, making the inside more positive. This is the action potential that allows the signal to be transmitted.

3. After the neuron fires, it needs to return to its resting state, a process called repolarization. Potassium ions rush out of the neuron, and the inside becomes more negative again.

4. However, the ion distribution is now opposite of what it was at rest. The neuron needs to restore the original distribution of ions. The sodium-potassium pump actively transports sodium ions out and potassium ions in, restoring the negative resting potential.

5. Therefore, for a neuron to return to rest, it must gain a negative charge.