HCO3/H2CO3 is the best buffer because it is:
pKa near physiological pH
Its components can be increased or decreased in the body as needed
Good acceptor and donor of H+ ions
Combination of a weak acid and weak base
Ans: B. Its components can be increased or decreased in the body as needed(Ref:Harper 30/e p11; Gaizung 25/e p6).HCO/H2CO3:Best buffer.As components can be increased or decreased in body as needed.Bicarbonate buffer system:Most powerful extracellular buffer in body.Since both elements of buffer system (HCO 3- & CO).Regulated respectively by kidneys & lungs.pH of extracellular fluid precisely controlled by HCO removal & addition by kidneys & CO 2 removal by lungs.