And to demonstrate this, let's examine the cell membrane of the cells found inside our lungs. So inside the cells of our lungs, we know we have a high concentration of carbon dioxide inside and a low concentration on the outside. Conversely, we have a low concentration of oxygen on the inside but a high concentration of oxygen on the outside. Now, both carbon dioxide and oxygen are small non polar molecules. And what that means is these two molecules will have no problem making their way and dissolving into that hydrophobic red core of that membrane. And so these oxygen molecules will naturally move spontaneously move from a high potential concentration to a low potential concentration from the outside to the inside.