6. Which of the following statements are accurate?
A. In an average, healthy human, the partial pressure of carbon dioxide is usually higher in the blood in systemic veins than the alveoli
B. In an average, healthy human, the partial pressure of oxygen is usually higher in the systemic veins than the alveoli
C. In average, healthy human, the partial pressure of oxygen is usually higher in the systemic arteries than in the body tissues
D. Generally speaking, gases will diffuse down their pressure gradient
E. In an average, healthy human, the partial pressure of carbon dioxide is usually higher in the body tissues than the systemic arteries.