Answer:
Traits other than beak type might affect natural selection.
It could take many generations to observe adaptions to a population.
The environment may be complex and hard to study.
Changes in the environment may occur faster or slower than changes to the birds
The birds may be interdependent with other organisms that may change, too.
Explanation:
19 chromosomes is prolly right.
D) The basic unit of structure and function in all living things
