It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. this is taken as evidence that the island forms and mainland forms are converging island forms are descended from mainland forms common environments are inhabited by the same organisms island forms and mainland forms have identical gene pools

Answer;

A) island forms and mainland forms descended from common ancestors.

Explanation;

-Islands tend to host very distinct but limited sets or species; on a given island a spectacular collection of one related group of species would be present and thriving, but many entire families or even higher taxa would be completely absent.

-All the species on the islands and the nearest continent are closely related to one another, however, each species had a set of adaptations that suits it for a particular environment. This means that the island forms and mainland forms descended from common ancestors.