Your roommate, who has not studied climate, says, "i thought the greenhouse effect was a bad thing. isn't it what's causing global warming? " which of the following statements might you use to your roommate understand the true nature of the greenhouse effect? select the two that apply. a. some gases, like carbon dioxide and water vapor, "trap" the heat radiated by earth, causing warming. b. earth would be more livable without the greenhouse effect. c. when there are more greenhouse gases in the atmosphere, the greenhouse effect is stronger. d. carbon dioxide is the only greenhouse gas that matters.