Now, because water is the main constituent of blood plasma that makes our blood aqueous. And that implies that oxygen, because it is non polar, it does not actually easily dissolve in the aqueous blood plasma. And so what happens, or what needs to happen is when oxygen gets into our lungs, it's the red blood cells that actually pick up that oxygen in the lungs and carry it to the cells of our body that need that oxygen to basically produce ATP for energy. Now, red blood cells are actually very specialized. They have very interesting structures, very interesting properties that make them very efficient for carrying oxygen. So let's discuss what these properties are.