Fill in the blank: some words will be used more than once, some not at all.
breathir 1. the exchange of oxygen and carbon dioxide between living cells an
vesa
system
n and carbon dioxide between living cells and their environment

Explanation:

1). the exchange of o2 and co2 happens mostly in the pulmonary arteries. Then travels through the bloodstream to oxygenate the cells throughout the body. This is also true to reoxygenate the cells to release co2

from the cells that travel back to the pulmonary arteries, all thru the bloodstream..