第9题: [单项选择]The crucial function of photosynthesis in terms of plant needs is______. A. to form sugars B. to combine carbon dioxide with water C. to preserve water D. to derive energy from light 参考答案:A 答案解析:仔细阅读第二段一开始对光合作用的叙述:"The processes of photosynthesis, by which carbon dioxide and water are combined