Answer:
answer b
Explanation:
air besarse plant produce air
B) assertive communication
I'd have to say d. the hand, because every human (for the most part, no offence intended to anyone) has a hand and is able to make good (or bad, rather) use of it. It's what a person always has access to at any given time or place, even if they don't have access to one of the other options.
Preventing and curing disease. i'm a medical student
ask me anything I know most