This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidneys and Body Fluids, Subject name: Physiology
Most important buffer system in human blood: 
Select and explain. 
A. Bicarbonates, B. Chlorides, C. Hb, D. Phosphates
A: Bicarbonates
Answer: A: Bicarbonates 
Explanation: Ans. a (Bicarbonates); (Ref. Ganong, Physiology, 21st ed., 736; Satyanarayan, Biochemistry 2nd ed. - 525)PRINCIPAL BUFFERS IN BODY FLUIDSBlood1. H2CO3 K H+ +HCO-3 (Bicarbonate buffer) =>>most predominant buffer of ECF. especially blood plasma.2. HProt K H+ + Prot- & HHb K H++ Hb- (Protein buffer)3. H2PO4 - KH-+ HPO42- (Phosphate buffer)Interstitial fluid1. H2 CO3 K H+ + HCO-3Intracellular fluid1. HProt K H+ + HCO 32. H2PO4 - KH-+ HPO42-