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. They will pass and dissolve inside and through that membrane. Likewise, these carbon dioxide, being non polar will also dissolve and move through that membrane via simple diffusion. But they will move from the inside to the outside down their concentration gradient.