The earth has precisely 78.09% of Nitrogen in its air.
Explanation: By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere.
Geographic means anything to do with the terrain or land. Isolation can happen for any amount of time, so you never know what the new population might be.
