Q - Today there are now at least thirteen species of finches on the Galapagos Islands and all of them evolved from one ancestral species, which colonized the islands a few million years ago. What steps lead to speciation and a diverse range of finch types?

Choices -
a - The ancestral finch was a ground-dwelling, seed-eating finch.
b - The ecological niches throughout the islands exert selection pressures that push specific birds in various directions.
c - In the original population of finches, variations existed.
d - Interbreeding among the various finch types resulted in greater physical and genetic variations.
e - Birds physically changed over time to be able eat the food resources that were available.
f - Different physical traits helped certain finches survive in certain niches, eating specific food.