The blood then flows through tiny capillaries, which surround the air sacs in the lungs, absorbing oxygen and giving up carbon dioxide, which is then exhaled.
(The blood; flows; through tiny capillaries; T:then) (tiny capillaries; surround; the air sacs in the lungs) (carbon dioxide; is exhaled; T:then)
The blood tiny capillaries carbon dioxide
flows surround is exhaled
through tiny capillaries T:then
the air sacs in the lungs
T:then