B organelles
Like the mitochondria
Hii! I believe the answer is D. The brown beetles were better able to survive to reproductive age and pass on their traits. (:
Answer:
Symbiosis is a close relationship between two species in which at least one species benefits. Mutualism is a symbiotic relationship in which both species benefit. Commensalism is a symbiotic relationship in which one species benefits while the other species is not affected.
They provide the immune system with "memory" against previously encountered pathogens.
T memory cells are necessary for protective immunity against invading pathogens
