Apolarized neuron in its resting state has a a. high potassium ion concentration on the outside of the cell membrane and a high sodium ion concentration on the inside of the cell membrane. b. high potassium ion concentration on the inside of the cell membrane and a high sodium ion concentration on the outside of the cell membrane. c. high potassium and high sodium ion concentration inside the cell membrane. d. high potassium and high sodium ion concentration outside the cell membrane.

B. high potassium ion concentration on the inside of the cell membrane and a high sodium ion concentration on the outside of the cell membrane.

Explanation:

Every response of a human to any situation occurs due to the working of network of neurons which take the stimulus from environment move it to brain and then produce a specific response.

The neuron normally stays in a polarized state when there is no external stimuli and it do not has to produce any response. In this case the membrane potential is –70 mV and there is a high potassium ion concentration on the inside of the cell membrane and a high sodium ion concentration on the outside of the cell membrane (please see figure). But when a stimulus of specific threshold greater than the resting potential is acheived, the situation reverses. Na+ channels open in the membranes and Na+ quickly start moving inside the membrane while K+ starts coming outside of the membrane This is called Depolarization which is later followed by subsequent events of  Repolarization  and Hyperpolarization .

Therefore, Option B is correct option.

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