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>
I believe that the correct answer is B. There are many articles that talk about how workers in Mexico are getting paid these low salaries for hard factory work.
