Which of the following is the correct flow of oxygen in the human body? 1. oxygen moves from the alveolus and enters the blood stream to capillaries. 2. air moves down through the trachea to the lungs. 3. blood full of oxygen moves to the heart and then out to body cells. 4. breathing in air through nose and mouth. 5. air moves to alveolus in the lungs.

Based on my understanding, we would have to capture that when breathing through oxygen, this oxygen would most likely go (first) through our lungs, and from here, the oxygen would then have to flow thought our body, to get the great feeling of actually breathing properly and to actually live.

So, based on your options listed above, they're several that seem to be the correct answer, but the main one that would really look like it would be the correct answer would be (Breathing in air through nose and mouth.) mainly because these are both the very important key aspects in the body.

Then Air moves down through the trachea to the lungs.

Air moves down through the trachea to the lungs.

Blood full of oxygen moves to the heart and then out to body cells. 

And then for last, I believe it would be Oxygen moves from the alveolus and enters the blood stream to capillaries.

I hope these are correct, and I was happy to help!