D) Diffusion helps gas exchange to occur
Answer:
scientist can learn how the rat has evolved based on where they live. it also helps find what the common ancestor was and all the common traits they have, for example rats in Norway may be used to the cold. and the rats in africa need to adapt to the heat and the constant threat of them being eaten.
Answer:
it effects the ozone which keeps out a majorty of the the suns raditon
