Finches developed special beaks that help them eat either insects or seeds, depending on which is more plentiful in their area. Why is this a good example of an adaptive function? Select one:
a. There is a lot of variation in beak type.
b. Different beak types make finches less likely to be eaten by a predator.
c. Finches learned to communicate about food options.
d. Different beak types help the finches survive in their environment.