Diffusion, specifically simple diffusion
The Lungs
The lungs
Im pretty sure carbohydrates carry oxygen through your bloodstream
I wouldn't exactly characterize it as separating carbon dioxide and oxygen, however, I think the answer you are looking for is the lungs which takes up oxygen into the bloodstream and expels carbon dioxide out of the bloodstream into the lungs so we can breathe it out again.
Carbon Dioxide
oxygen
hemoglobin
Lungs
Oxygen is breathed through the nose or mouth and travels to the lungs through the bronchial tubes, then absorbed through the alveoli into the bloodstream. In the bloodstream the oxygen is transported all over the body by red blood cells. So, red blood cells would be your answer.
The lungs absorb oxygen (O2) and it is carried in hemoglobin through the bloodstream to various cells.
The preponderance of oxygen is carried through the rectum
Oxygen enters your nose,then goes through the trachea,to the bronchi,and last to your lungs.
The lungs supplies the bloodstream with oxygen. When we breathe in, out lungs fill with oxygen and that oxygen is taken to the heart to keep our body going.
The process in which oxygen enters the bloodstream through the alveolus and carbon dioxide exits the bloodstream also through the same alveolus to be exhaled.
Through the bloodstream, dissolved in the blood and bound to haemoglobin,
oxygen
oxygen that is inhaled into the lungs is diffused through the small air sacs, called alveoli, into the bloodstream.