Regarding nitrogen fixation, are the following statements True or False? a) Atmospheric nitrogen is reduced to the biologically useful form NH 3 (or NH 4 ). b) Nitrogen fixation in

Regarding nitrogen fixation, are the following statements True or False? a) Atmospheric nitrogen is reduced to the biologically useful form NH 3 (or NH 4 ). b) Nitrogen fixation in nature and in the lab requires a metal cofactor or catalyst. c) The availability of fixed nitrogen limits biological productivity. d) Ammonium from the atmosphere is fixed to more usable forms of nitrogen, such as nitrite (NO 2 – ). e) Nitrogen fixation is energetically neutral, using a negligible amount of ATP. f) The enzyme nitrogenase, which takes part in nitrogen fixation, is inactivated by oxygen.