题目

Look, there is a notice on the wall of the restaurant. -It tells us that it’s better to eat up food we have ordered. It’s called “empty ______”. A. plates         B. bowls       C. CDs              D. spoons 答案：A遗传信息库是（　　）A.细胞膜B.细胞质C.细胞核D.细胞壁