And what that means is, by binding to our hemoglobin, what carbon monoxide does is it creates a leftward shift in our curve. The question is, why does this actually take place? And what physiological consequence does this actually have on the tissues of our body? Well, basically, when carbon monoxide binds onto the heme group of hemoglobin, it makes the other empty heme groups much more likely to actually bind oxygen molecules. So, by binding to our hemoglobin, carbon monoxide makes or increases the affinity of hemoglobin to oxygen. And that's exactly what creates this leftward shift in the first place.