Which Statement About the Transport of Respiratory Gases by the Blood

Multiple Choice

Which statement about the transport of respiratory gases by the blood in humans is true?

A) The amount of O₂ that can be dissolved directly in plasma is sufficient to support the resting metabolism.
B) By binding O₂, hemoglobin prevents an O₂ concentration gradient from forming between the blood and the tissues.
C) Internal perfusion of the gas exchange surfaces is dependent on blood flow.
D) Each hemoglobin molecule can carry a maximum of two O₂ molecules.
E) Molecules of O₂ are associated with the polypeptide subunits of hemoglobin.