Has anyone had the lab with the question,"how does natural selection change the phenotypes within a population over time? " if so can you me with a few questions

Natural selection causes the allele frequencies in a population to change over time. The allele which contributes to better traits will be present in abundance in a population. Organisms which are better adapted to live in an environment and which are better adapted to change with the changing natural conditions are able to survive and reproduce. Hence, over time those phenotypes will be present in abundance which are better able to survive and adapt to the changing conditions.

digestion

it excretes wastes