From FDRâs brushes with death to Eleanorâs midnight ride with Amelia Earhart, here are 10 things you may not know about this presidential pair. 1. Franklin Roosevelt was related to 11 other presidents.
By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% 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.y volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% 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.
The pie chart shows the proportions of the main gases in the atmosphere. The composition of air. The two main gases are both elements and account for about 99 percent of the gases in the atmosphere. They are: 1  about 4 / 5 or 80 percent nitrogen (a relatively unreactive gas).2  about 1 / 5 or 20 percent oxygen (the gas that allows animals and plants to respire and for fuels to burn).he two main gases are both elements and account for about 99 percent of the gases in the atmosphere. They are: 1  about 4 / 5 or 80 percent nitrogen (a relatively unreactive gas).