This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Medicine
[{'content': 'The key factor in the transpo of carbon dioxide as bicarbonate is \nSelect and explain. \nA. The high solubility of CO2 in H20, B. The presence of Hb in blood, C. The presence of carbonic anhydrase in the erythrocytes, D. The acid nature of carbon dioxide and the alkaline nature of bicarbonate', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Since the Pco2 in the tissue is high,CO2 diffuses from tissues into the plasma. From there it enters the RBC which contains plenty of carbonic anhydrase. In blood,70% of CO2 is transpoed as HCO3 by the action of carbonic anhydrase. Reference:Textbook of medical physiology-Geetha N,2nd edition,page no:245.', 'role': 'assistant'}]