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': 'Percentage of 02 carried in chemical combination \nSelect and explain. \nA. 97%, B. 3%, C. 66%, D. 33%', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. 97%;', 'role': 'assistant'}]