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. In the resting state, the intracellular spaces (inside) has higher concentration of K⁺ ions and the extracellular spaces (outside) has high concentrations of Na⁺ ions.
The rapid changes in the membrane potential of a cell gives rise to the action potential.
During an action potential, the Na⁺ ions move inside the cell into the intracellular spaces, thus increasing the concentration of Na⁺ ions inside the cell.
Therefore, the sodium levels increases inside the cell, during an action potential.
