The Partial Pressure of Oxygen in the

Multiple Choice

The partial pressure of oxygen in the

A) atmospheric air averages 79 percent of total atmospheric pressure
B) blood is the most important factor that determines the extent to which O₂ will combine with hemoglobin
C) arterial blood is decreased when hemoglobin preferentially combines with CO rather than O₂
D) atmospheric air averages 79 percent of total atmospheric pressure, and blood is the most important factor that determines the extent to which O₂ will combine with hemoglobin
E) all of these