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
[{'content': 'Which ion helps is resting membrane potential in neurons: September 2005, March 2013 \nSelect and explain. \nA. Potassium, B. Calcium, C. Chloride, D. Sodium', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A: Potassium In neurons resting membrane potential is about -70 mV, which is close to the equilibrium potential of potassium ions', 'role': 'assistant'}]