Why must aerobic organisms such as yourself breath oxygen and exhale co2?

Aerobic organisms like humans are dependent on oxygen for their survival because in us without oxygen formation of ATP(energy) can not be possible.

In aerobes, oxygen acts as the final electron acceptor in the electron transport chain after which oxygen converts into H2O and formation of ATP occurs. Therefore we have to breathe oxygen continuously so that our cell can form ATP.  

CO2 is a byproduct of aerobic respiration in which is generated when glucose gets oxidized into CO2, therefore, we exhale this CO2 through our lungs.  

the main thing i would use is bricks because if there is a hurricane, there is a great possibility for the house to still stand. and i would also use plexiglass windows instead of regular windows because plexiglass isn't prone to breaking.

carbon atoms, hydrogen, oxygen, and nitrogen.