How do buffers work in the human body?

They can help prevent a deadly change in blood pH. They can help keep blood below pH 7.0. They can help keep blood at a pH of 7.0.

Explanation:

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.