• aa

     INPUT                                          
    		 TRANSFORMATION / OUTPUT
     Atmospheric Nitrogen
           aa or AA


    		 DIE ROLL
     
    		 1 Lightning! aa Soil aa
      2 Lightning! aa Soil aa
      3 Nitrogen Fixation by Rhizobium bacteria in legume root nodules (clover) aa aa
     
     4 Nitrogen Fixation by Rhizobium bacteria in soil only
     aa aa
     5 - 6  Cyanobacteria fix atmospheric aa into oceanic aa