What is the pathway for co2 in our respiratory system?

Carbon dioxide (CO2) is a waste product of cellular metabolism. You get rid of it when you breathe out (exhale). This gas is transported in the opposite direction to oxygen: It passes from the bloodstream – across the lining of the air sacs – into the lungs and out into the open.

More than 600. i'm just guessing

Is that a negative 22 or a positive?