And by binding oxygen onto that hemoglobin molecule, all we're doing according to this model is shifting the equilibrium between the two states. And to see what we mean, let's take a look at the left side of this diagram. So on the left side, right here, none of the heme groups on the hemoglobin actually contain oxygen. And so what that means is the error going this way will be much longer than the error going this way. And what that means is, in this particular situation, when we have deoxy hemoglobin, when none of the heme groups contain an oxygen, the structure will be predominantly and almost exclusively in the t state. Now, what happens when we bind a single oxygen onto that hen group?