Answer:
environment, convergent evolution
Explanation:
When two species with no immediate common ancestors are exposed to same kind of environment they might develop body parts which have similar functions leading to convergent evolution. The resultant body parts are known as analogous structures. Here, both Patagonian hares and England rabbits were exposed to similar environment so even though their body structures had different origin, they developed to be similar in function. They are in contrast to homologous structures which develop due to divergent evolution where the origin of the structure is same but they diverge due to different functions.
