In what form is carbon found in the atmosphere

Carbon dioxide or CO2 because when we breathe out thats what we release, and CO2 cant re-enter our body. Thats why people evantually run out of air in tight spaces, Because they turn all the air into CO2

If there was no gravity then their would be no downword force on the football to have it return the the grownd, and if there was no friction (mainly air friction) then there would be no opposing force the stop the ball from moving through the air allowing the ball to travle ∞.