original: it is 78 % nitrogen and 21 % oxygen , with trace amounts of water vapor , carbon dioxide and other gaseous molecules .
simplifications: it is 78 % nitrogen , 21 % oxygen and trace amounts of gaseous molecules . it is 78 % nitrogen and 21 % oxygen , with small amounts of water vapor , carbon dioxide and other gaseous molecules . it is 78 % nitrogen and 21 % oxygen with trace amounts of water vapor , carbon dioxide and other gaseous molecules . it is 78 % nitrogen and 21 % oxygen , with trace amounts of water vapor , carbon dioxide and other gaseous molecules . it is made up of 78 % nitrogen and 21 % oxygen , as well as very small amounts of water vapor , carbon dioxide and other gas molecules . it is 78 % nitrogen and 21 % oxygen , with small amounts of water vapor , carbon dioxide and other molecules in the form of gas . it is made up on 78 % nitrogen , 21 % oxygen , small traces of water vapor , carbon dioxide and other gaseous molecules . it is 78 % nitrogen and 21 % oxygen , with trace amounts of water vapor .