CER- If the air we breathe is majority nitrogen, why do humans breathe oxygen? It seems like we are using the second most abundant gas. Seems very inefficient if you ask me. In terms of chemistry how does oxygen help
our body more then nitrogen?

it should be all of them because it asks if you included all of those in your answer

explanation:

its first and third is your answer i did the qustion the fourth isnt right

a saline water is fed to a reverse osmosis unit at flow rate o rotameter connected to reject (retentate) line reads 8 installed in reject and permeate line reads 15.2 milli siemens/cm and 300 micro siemens/com respectively.