Where is the concentration of oxygen the highest in our bodies, and where is it the lowest? How would the distribution of oxygen in our bodies be different if we still had lungs, but not a circulatory system?

The air in the lungs has a higher concentration of oxygen than that of oxygen-depleted blood and a lower concentration of carbon dioxide.

the body would divert most of the oxygenated blood to the brain and heart (the most important organs), but that would only last a while, and eventually the brain would force the diaphragm to move, and you to breathe.

i think the answer would be d