The Species of Finches,tortoises,cacti,iguanas,and Many Others That Are Found on the Galápagos

The species of finches,tortoises,cacti,iguanas,and many others that are found on the Galápagos Islands are found nowhere else in the world.Which physical attribute of these islands has not played a role in permitting such unique life forms to evolve?

A) There is geographic isolation from mainland species.
B) Multiple islands exist.
C) Food is plentiful and diverse on every island.
D) The islands are small compared to the South American mainland.
E) Each island has its own unique environment.