Many Species of Finches, Tortoises, Cacti, and Iguanas Are Found

Many species of finches, tortoises, cacti, and iguanas are found on the Galápagos Islands and 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. Island clusters such as the Galápagos offer opportunities for multiple species to evolve since they are isolated, small, have different environments, and food is often either scarce or different from that available on the mainland.