It is in the Texas Blackland Prairies.
Nitrogen (78%), Oxygen (21%), Argon (0.9%), and the remaining 0.1% consists of traces of neon, krypton xenon, carbon dioxide, nitrogen oxides, and traces of others. so Nitrogen is the greatest. I hope this helps :)
Air masses form because of air pressure, which causes tornado fronts.
The proper answer would be Greenland