13. Which of the following is correct concerning the differences between hemoglobin and myoglobin?
(A) Both hemoglobin and myoglobin are tetrameric proteins.
(B) Hemoglobin exhibits cooperative binding of O₂ while myoglobin does not.
(C) Hemoglobin exhibits a hyperbolic O₂ saturation curve while myoglobin exhibits a sigmoid shaped curve.
(D) Hemoglobin exhibits a higher degree of O₂ saturation at all physiologically relevant partial pressures of O₂ than does myoglobin.