题目

People use their mouths for many things. In the English language, there are many expressions using the word “mouth”. But some of them are not so nice.Sometimes, people say something to a friend or a family member. Later they regret because it hurts that person’s feelings. Or they tell the person something they didn’t mean to tell. The speaker might say: “I really put my foot in my mouth this time.” Sometimes when one person is speaking, he says the same thing that his friend is going to say. When this happens, the friend might say: “You took the words right out of my mouth!” So下列关于遗传物质的说明，正确的是（　　） A、DNA每个碱基上均连接一个磷酸和一个脱氧核糖B、不同DNA分子中(A+T)(C+G)比例是不变的C、来自同一玉米果穗的籽粒遗传信息不一定相同D、噬菌体浸染细菌实验能证明DNA是主要的遗传物质