Answer:
Nitrogen like other elements is cycling between air and soil in different forms.
Explanation:
When Nitrogen is in the air, there are some specialized bacteria (Nitrogen fixing bacteria) which are capable of transform gas Nitrogen in "solid" Nitrogen that can be asimilated by plants, these bacteria are asociated with plants and live in symbiosis in their roots. Nitrifying bacteria can also transform the Nitrogen in the air and fix it into the soil and denitrifying bacteria can transform soil Nitrogen ,in atmospheric Nitrogen which is present in the air to keep the Nitrogen cycle.
