Originally Posted by Oscar98
I hope that was sarcasm. Have you ever been in health/science class? We USE oxygen. So why would we EXHALE mostly oxygen???
Wow I suggest you do some research before you state fact. (Which by the way is completely wrong) I figure you must still be in high school or something. As someone with a university degree in science I've learnt the hard way to always check facts prior to stating them. The human body just like a typical car engine does not burn fuel (ie oxygen for humans) in the most efficient manor that is the reason we only use about 7-8% of the 21% oxygen we breath in, and yes that is exactly how CPR/rescue breathing works