Rebekah

The bigger the density, the heavier the gas, the more it sinks. The oxygen would rise because it's lighter, etc.

@AwesomelyEpic5284 why?

Oh! And oxygen is heavier than most of the gases in the air. It wouldn't be up too much. :)

Lolz i fanned you cuz i love that song :D

Lol no problem. I'm a big whovian and love the Walking Dead. 

Ta muchies for following x or fanning xD I don't know which one it is anymore lol

Check out Chapter two! 
          

Nerd

Actually you should want oxygen in your lungs rather than in the air.

Oxygen I hope.