Darwin's finches are an ancestral mainland finch species that arrived on the galápagos islands and evolved into about 15 new species through adaptive radiation, while the finches on the mainland did not. what is the most plausible biological explanation for this?
options:
a- adaptive radiation happened because of the isolation of the islands.
b- lack of competition on the island allowed for greater utilization of resources by the finches.
c- the environment on the mainland was completely uniform, unlike the galápagos.
d- the founder effect greatly expanded the variation in alleles in the galápagos finch gene pool.