A new theory presented by Princeton University researchers in the journal Nature Plants suggests that the plants aren't just passive features of their environments, but the ecosystems of the world take their various forms because plant "decisions" make them that way. http://www.princeton.edu/main/news/archive/S44/88/96G13/ More info on nitrogen fixation: https://www.researchgate.net/public...ted_by_climatic_constraints_on_nitrogen_cycle
