Answer: The level of oxygen that the body is getting is low so it would most likely start to breath faster. By doing that the heart rate will also increase so that the blood can deliver the oxygen to the tissues. Over all the body will produce more red blood cells to use the oxgen efficiently.
Answer: The path of an oxygen molecule is oxygen outside - it is breathedinto the lungs. Then it is absorbed into the blood vessels in thelungs and attaches to a hemoglobin molecule - the hemoglobinmolecule carries the oxygen now into the heart and is pumped out tothe body from the aorta - when the blood reaches an area that islow in oxygen it releases oxygen, which leaves the blood vessel andis absorbed into the tissue.
Answer: It may help to step back and think about what blood does, and why it would matter that the blood is rich in oxygen (or CO2).Among other things, blood acts to transport oxygen and CO2 to or from tissues and organs, right? In order for the blood cells to carry them, the binding site on the blood cell would have to be open.So, if the blood is oxygen rich, that means that those blood cells are carrying as much oxygen as they can...there is simply no room for any CO2 to bind to the cells.So the reason it never mixes is because the oxygen is hogging the blood cells binding sites (or vice versa).