When members of the same species become adapted to new environments
A plant-life filled biome of sorts, like a thick forest.
Hope this helps!
Explanation:
Biosphere. It is the highest level of organization. It is the global ecological system which consists of all the living organisms and other factors which supports life.
C is your answer so pick c
They provide the immune system with "memory" against previously encountered pathogens.
T memory cells are necessary for protective immunity against invading pathogens