This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment, Subject name: Social & Preventive Medicine
[{'content': 'Green-house gases not include: \nSelect and explain. \nA. Carbon dioxide, B. Carbon monoxide, C. Water vapour, D. Methane', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Global warming /Green house effect is caused by heat-trapping gases in the atmosphere released by burning of fossil fuels, depletion of ozone layer, d/t use of aerosolized chloro-fluoro-hydrocarbons etc. By their % contribution to greenhouse effect on eah, 4 major gases: Water vapour, 36-70 % Carbon dioxide 9-26% Methane 4-9% Ozone 3-7%', 'role': 'assistant'}]