The primary purpose of the digestive system is to create human tissue from nonhuman foods

provide energy for useful work

break down food into a size that can be absorbed

produce feces and other wastes

ok yes, but what is the question? as soon as you ask the actual question i will answer it. : )

i believe it's c. the trait for large beaks will be passed on to future generations through natural selection.

since eventually smaller beaks would have to find another source of food or even eventually just die out from the lack of food.