It really is between C.or D. I say it is D. because you need the <span>experimental subjects in the best condition possible to get the best results.</span>
Answer:
Oxygen enters the blood stream through the alveoli, which are tiny air sacs in the lungs where gas change is exchanged. Carbon Dioxide goes in through the alveoli and out goes oxygen.
2. air sacs
Hope this helps ;)
There is an angler fish and the boat from the titanic