Explanation: What are you talking about here is it about the exports imports? Is it about their valubale resources. Please elaborate.
Plants have these because root nodules<span> are formed when nitrogen fixing bacteria called "rhizobia" start to enter the cells of a host </span>plant<span>. Rhizobia normally live inside of the soil and they </span>can<span> exist without a host </span>plant<span>.</span>
B; As far as the relation between humans and the environment, it is obvious how much they relied on it. Not only as a food source, but for economic growth and sustainability as well. The other answers make valid points but in the context of this question, the only one that even mentions the relation is B.