This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Renal physiology, Subject name: Physiology
[{'content': 'Buffering action of haemoglobin is mainly due to \nSelect and explain. \nA. heme, B. Porphyrin, C. Imidazole group of histidine, D. Histidine group of imidazole', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The buffering action of hemoglobin is due to the imidazole group of the hystadine residues. Hemoglobin molecule contains 38 histidine. imidazole group of deoxyhemoglobin dissociate less than those of oxyhaemoglobin. Ref: Page no 566 Textbook of physiology Volume 1 AK Jain 7th edition', 'role': 'assistant'}]