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: Physiology
[{'content': 'Oxygen comes from alveoli to blood by- \nSelect and explain. \nA. Diffusion, B. Receptor mediated, C. Active transport, D. Osmosis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Diffusion(Ref: Ganong, 25th ed/p.640)Diffusion means movement of molecules from area of high concentration to area of low concentrationGas exchange in lungs happens in the form of diffusion in lungs', 'role': 'assistant'}]