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
Most abundant ion in intracellular fluid is:September 2008, September 2012, March 2013 
Select and explain. 
A. Protein, B. Bicarbonate, C. Potassium, D. Sodium
C: Potassium
Answer: C: Potassium 
Explanation: Ans. C: PotassiumIntracellular component of the body water accounts for about 40% of body weight and extracellular component for about 20%.Concentration of potassium in cytosol is 139 millimeter and of Amino acids (in proteins) is 138 millimeter,