Why does all mammals have seven vertebrae (bones) in their neck? A) all mammals descended from a common ancestor
B) predators only eat animals with six neck vertebrae
C) all animals can turn their heads the same amount
D) all mammals have to stretch their necks to obtain food

C I hope I'm right

bacteria could be both, harmful and to us. harmful bacteria could make us sick and probably even by getting the chances of getting a disease, but good bacteria fight it off with your immune system. there is always bacteria everywhere we go. we need to make sure to wash our hands after using the restroom, before eating, after eating, after petting an animal too. so you see, bacteria is everywhere and is harmful or . i hope this . : ) : ) : )