I'm just guessing since this is my prediction. Either B. or D. I dont know about C. and it is definitely not A. since the lumber companies are only taking down some trees instead of all of them.
Plant cells have cell wall but animal cells don't have any cell wall.
If the beavers need large teeth to collect wood for their dams, the population of beavers with larger teeth will live longer because they can collect wood. They will them be able to reproduce therefore passing down the gene with larger incisor teeth
