There is hardly an environment on earth some species of animal or other have not adapted

问题补充：

There is hardly an environment on earth some species of animal or other have not adapted successfully.

A. to which

B. in which

C. for which

D. on which

答案：

A. to which

B. in which

C. for which

D. on which

解析：考查定语从句：先行词是an environment，定语从句中adapt后面缺少介词to，用to which引导定语从句。句意：地球上很难有一种环境，一些动物和其他的物种不能成功的适应的。选A。