I don't know ask someone else. I think the answer is cheese.
The lungs diffuse oxygen into the bloodstream. Oxygen from the air we breathe is absorbed into the bloodstream through the walls of the alveoli in the lungs, where it is then carried by red blood cells to be delivered to the body's tissues.
Oxygen
No, the movement of oxygen from the lungs to the bloodstream is not by osmosis. Instead, it occurs through a process called diffusion, where oxygen molecules move from an area of high concentration (in the lungs) to an area of lower concentration (in the bloodstream) to reach equilibrium.
Lungs
Oxygen is the gas that passes from the lungs to the bloodstream.
Your bloodstream can't store oxygen for an extended period; it just transports it from the lungs to where it is needed.
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.
Lungs
+++Osmosis
Yes, when we breathe in, oxygen from the air enters our lungs. This oxygen is then absorbed into the bloodstream through tiny air sacs in the lungs called alveoli.
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.
oxygen