This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Principles of Gas Exchange -  Respiratory Membrane, Subject name: Physiology
[{'content': '% of O2 inhaled- \nSelect and explain. \nA. 5%, B. 20%, C. 50%, D. 78%', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., 20% Atmospheric (inspired) airAlveolar airExpired air %PP mm Hg%PP mm Hg%PP mm HgO220.8415813.410016116CO20.040.35.340432Nitrogen78.6259675.157374.1565H2O (vapour)0.505.76.2476.247 100760100760100760", 'role': 'assistant'}]