This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Resting membrane potential is close to the isoelectrical potential of: 
Select and explain. 
A. Na., B. Cl., C. K, D. Mg
B: Cl.
Answer: B: Cl. 
Explanation: Resting membrane potential of nerve is -70 mvd/t K channels. And it is equal to equilibrium potential of chloride ion (-70 mv).