Why is the resting membrane potential (Vm) approximately - 70 mV for most cells? Most cells contain a large concentration of Cl - making them negatively charged. The large concentration of proteins in the interstitial space draws Na + out of the cell making it negatively charged. Most membranes are 10 times more permeable to Na + than to K+. Most membranes are 40 times more permeable to K + than to Na+.

Option (4).

Explanation:

Cell membrane potential may be defined as the difference in the electric potential between inside and outside of the cell. This potential is important for the action potential.

The resting membrane potential of the cell is - 70mV. This membrane potential is maintained by the potassium ions of the cell. The cell membrane are almost 40 times more permeable to potassium ions than sodium ions and makes the cell membrane potential negative.

Thus, the correct answer is option (4).