题目

From the health point of view we are living in a marvelous age. But though the possibility of living a long and happy life is greater than ever before, every day we witness the incredible slaughter（屠杀） of men, women and children on the roads. Man versus the motor-car! It is a never-ending battle which man is losing. Thousands of people the world over are killed or horribly killed each year and we are quietly sitting back and letting it happen. It has been rightly said that when a man is sitting behind a steering wheel, his car becomes the extension of his personality. There is n细胞增殖是生物体内一项重要的生命活动。如图是某高等植物细胞有丝分裂周期图，请据图分析，说法不正确的是                                                                                                                （    ）        A．一个完整的细胞周期应为3→2→1→E→F→G→H        B．D过程叫做细胞分化，其实质是基因的选择性表达        C．C过程中多倍体细胞的出现，必须要经过秋水仙素的处理        D．细胞周期中，一个细胞中具有形态和数目完全相同的两套染色体的是G时期