In respiration we inhale 21% O2 & 0.04% CO2 and exhale 16.4% O2 & 4.4% CO2.
But if you calculate then 21-16.4 = 4.6 while 4.4-0.04 = 4.36.
That disturb the Mole concept in chemistry point of view.
In my opinion it leaves body in form of bicarbonate.
Correct me please.