Question

a neuron has a negative electrical charge of about 70 millivolts when it is

not covered by a myelin sheath.

in a resting state.

covered by a myelin sheath.

firing.

Explanation:

To solve this, we analyze each option:

• "Not covered by a myelin sheath" relates to axon structure, not resting potential charge.
• "In a resting state": A neuron's resting membrane potential is typically around -70 millivolts, matching the description.
• "Covered by a myelin sheath" affects signal transmission speed, not resting charge.
• "Firing" (action potential) involves a positive charge spike, not -70 mV.

Answer:

B. in a resting state.