So let's begin by recalling some basic biological facts. Inside our lungs, the partial pressure of oxygen is about 100 mercury inside our resting tissue. When we're not exercising, the partial pressure drops to 40 mercury. And inside our exercising tissue, for example, if we're swimming or running, our partial pressure drops to about 20 mercury. So we want to use these values and the oxygen dissociation curves for myoglobin and hemoglobin to basically show why hemoglobin is a much better carrier of oxygen than myoglobin. So let's begin with the hemoglobin.