Stephen Hawking believes that the carts is unlikely to be the only planet ( ) life has developed gradually .

问题描述:

Stephen Hawking believes that the carts is unlikely to be the only planet ( ) life has developed gradually .
A that B,where C,which D,whose

B.wherewhy ?可以分析一下吗where 作定语从句life has developedgradually 的地点状语,即 life has developedgradually (in the planet)