Atmospheric nitrogen is directly replenished in nature through
the activities of denitrifying bacteria
the breakdown of ammonium salts in the soil
the activities of nitrifying bacteria
the activities of nitrogen-fixing bacteria in root nodules
egestion, death and decay
Correct answer is A
The nitrogen in the soil is converted to atmospheric nitrogen by the process of DENITRIFICATION. This is done by the action of denitrifying bacterias eg several species of Pseudomonas.