And what that means is our hemoglobin keeps the oxygen protected and it keeps the oxygen comfortable within that hydrophobic section of the inside of our hemoglobin. So, remember, the outside of the protein is polar, but the inside of the protein where we have the oxygen is a hydrophobic portion. So it's non polar. And that's why oxygen can reside comfortably within these four sections of our hemoglobin. Now, let's suppose we take a small cross section of our capillary. Let's suppose this is some capillary inside our blood system.