This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Excretory System (Kidney, Bladder) Acid-Base Balance, Subject name: Physiology
[{'content': 'The most impoant buffer in interstitial fluid: \nSelect and explain. \nA. Phosphate, B. Bicarbonate, C. Histidine, D. Protein', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The chemical buffer systems in the body - bicarbonate system, phosphate system, and the proteins. Bicarbonate buffer is quantitatively the most impoant buffer in ECF compament; it buffers non-carbonic acid. Hence, option B is correct. Intracellular proteins account for >70% of I/C buffering . Phosphate helps in intracellular buffering .', 'role': 'assistant'}]