题目

下列物质中与纤维素和胆固醇两种化合物元素组成最相似的一组是A.糖原、胰岛素、性激素 B.淀粉、糖原、性激素C.性激素、磷脂 D.DNA、RNA 答案：【答案】B【解析】纤维素属于多糖，胆固醇属于固醇类，其元素组成均为C、H、O，据此分析作答。A、胰岛素的化学本质为蛋白质，其元素组成主要为C、H、O、N，A错误；B、淀粉、糖原均属于多糖，性激素属于固醇类，其元素组成均为C、H、O，B正确；C、磷脂的元素组成为C、H、O、N、P，C错误；D、DNA和RN根据短文内容，判断正误。It's a sunny day. Daming goes to a park with his friend, Tom. There are many people in it. Two little boys are singing under the tree. An old man is running around the lake. Some girls are flying kites. Two men are playing chess. Daming and Tom like boating. Look! They are very happy in the boat.【1】Two little boys are dancing under the tree. （_______）【2】An old man is running around the lake. （_______）【3】Some girls are flying kites. （_______）【4】Two men are playing chess. （_______）【5】Daming and Tom are in the boat.（_______）