Dear friends,
   My name is Helen. I'm 12 years old. I  1  from Taxas, America. I’m really  2   in Chinese geography. It's fun! And I hope you can tell me more. I like hamburgers best,  3   I try to eat them twice a week  4   it's a kind of   5   food. And I like to drink lemon  6   . As for sports, I often go swimming with my parents on weekends.
   I   7  in Cobb Street School. My   8  subjects in school are ME and art. They are really fun! After school, I like to go to the   9   with my family or friends. I like action movies and cartoons. They’re  10   How about you? Do you often go to the cinema with your family or friends?
                                                                                                                                                                   Yours,
                                                                                                                                                                   Helen

步骤1：剔除大蒜蒜瓣和红葱的老根，置于装有适量清水的烧杯中，在20～25℃下培养，每2d更换一次清水．

步骤2：待大蒜和红葱的须根长出后，每24h测量须根长度，记录并处理数据．结果如图1．

步骤3：若干天后，从8：00～16：00，每2h取生长健壮的须根根尖制成临时装片．观察时随机选取30个视野，统计各视野中分裂期细胞数以及细胞总数，并计算细胞分裂指数（分裂期细胞数/细胞总数）．结果如图2．

分析回答：

氧化反应和化合反应两者的关系是（     ）