Stream channeled flow of water,regardless of size
A man is 100,000 times larger in micrometers than the amoeba, since 17 micrometers is 0.000017 meters, and 1.7 meters is 1,700,000 micrometers
Nitrogen fixation, N2 --> NH3+, is not something that plants to by themselves but some plants have bacteria that does this. I believe that pea plants have these, but I'm not 100% sure.
The correct answer is B !! Both are interdependent thus forming a mutualistic association !!
As both can not live without each other thus making obligate !!
so They share obligate mutual association !! Go with B !!
