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
[{'content': 'Most important buffer system present in the distal convoluted tubule \nSelect and explain. \nA. Bicarbonate, B. Phosphate, C. Protein, D. Ammonia', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Most important buffer in proximal tubules - Bicarbonate\nMost important buffer in distal tubules - Ammonia', 'role': 'assistant'}]