What is special about nitrogen, and what is its main function in the atmosphere

Our atmosphere is made up of 78% nitrogen, 21% oxygen and 1% other gas. Nitrogen is so special because if the air was just made up of oxygen and if that were so then the vary air that we breath would be very flammable and would toxic to us. Thus this is why we have Nitrogen.

We as humans need Nitrogen to survive. We breath 78 percent nitrogen and 21 percent oxygen