Answer: possibly A
Explanation: B an C are not it because they are more like mutations. D humans don’t always become immune.
Answer:
Bacteria play a central role
Explanation:
Nitrogen-fixing bacteria, which convert atmospheric nitrogen to nitrates. Bacteria of decay, which convert decaying nitrogen waste to ammonia. Nitrifying bacteria, which convert ammonia to nitrates/nitrites.
Adrenaline which creates the “fight or flight respond” basically amplifying the function of many of the body’s internal parts to allow someone to escape from a lion.
Answer:
structures are responsible for particular functions, and the cell membrane forms the boundary that controls what enters and leaves the cell
Explanation:
(In multicellular organisms, the body is a system of multiple interacting subsystems)
