She ______ to Africa to study the animals there, even though her family asked her not to.

A．insisted on going

B．insisted going

C．insisted in going

D．insisted to go

最能表明一个细胞具有特殊功能的是[ ]

A．细胞核的大小

B．细胞器的种类和数量

C．细胞膜的特性

D．细胞膜的结构