At the same time, carbon dioxide leaves the blood and enters the lungs to be breathed out.
(carbon dioxide; leaves; the blood; T:At the same time) (carbon dioxide; enters; the lungs to be breathed out; T:At the same time) (the lungs; to be breathed out; )
carbon dioxide carbon dioxide the lungs
leaves enters to be breathed out
the blood T:At the same time
the lungs to be breathed out T:At the same time