Answer:
The correct answer is: INCREASES
Explanation:
The membrane potential of a cell is defined as the difference in the electric potential between the outside and inside of the cell.
Ions such as sodium (Na⁺) and potassium (K⁺) ions, have a concentration gradient across the cell membrane.<em> In the </em><em>resting state</em><em>, the intracellular spaces (inside) has higher concentration of K⁺ ions and the extracellular spaces (outside) has high concentrations of Na⁺ ions.</em>
The rapid changes in the membrane potential of a cell gives rise to the action potential.
<em>During an </em><em>action potential</em><em>, the Na⁺ ions move inside the cell into the intracellular spaces, thus increasing the concentration of Na⁺ ions inside the cell.</em>
Therefore, the sodium levels <u>increases</u> inside the cell, during an action potential.