题目

It’s 9 a. m. , the morning rush hour in Toronto. A man has fallen down on a downtown street suddenly. Several passers-by stop to help the man. One woman reaches into her purse for her cellphone and hits 911, the emergency number.    36   Within ten minutes, the stricken(患病的) man is in the back of an ambulance and is sent to the hospital for life-saving treatment. This scene is fairly common in Toronto and other major cities. Over the years, cities have developed systems to respond quickly to emergencies.    37   But none of this would be possible without the cooperat细胞学说是现代生物学的基础。下列哪项不是细胞学说的主要内容 A．所有的生物都是由一个或多个细胞组成的 B．细胞是所有生物的结构和功能的单位 C．所有的细胞必定是由已存在的细胞产生的   D．动物细胞和植物细胞在结构上是有区别的