Final answer:
The oxygen carrying capacity of human blood is about 20 vol %, with the majority of oxygen being bound to hemoglobin in red blood cells.
Step-by-step explanation:
Oxygen Carrying Capacity of Human Blood
The capacity of human blood to carry oxygen is primarily due to the hemoglobin in red blood cells. Hemoglobin is a metalloprotein that can bind up to four oxygen molecules per molecule of hemoglobin. While a small amount - approximately 1.5 percent - of oxygen in blood is dissolved directly, the vast majority, 98.5 percent, is bound to hemoglobin. Given that each hemoglobin molecule can carry four molecules of oxygen, the oxygen carrying capacity of human blood is approximately 20 vol %.