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
Potassium concentration in which of the following is responsible for maintenance of cardiac and neural function? 
Select and explain. 
A. Intracellular, B. Extracellular, C. Intravascular, D. Extravascular
A: Intracellular
Answer: A: Intracellular 
Explanation: Potassium is most concentrated inside the cells of the body. The gradient or the difference in concentration from within the cell compared to the plasma, is essential in the generation of the electricial impulses in the body that allow muscles and the brain to function.