Which of the following statements about hemoglobin is true? a. for any given o2 partial pressure, the oxygen saturation for hemoglobin is higher than for myoglobin. b. the binding of oxygen to a hemoglobin molecule diminishes the binding of additional oxygen to the same hemoglobin molecule. c. the glycolysis intermediate, bpg (2,3-bisphosphoglycerate) raises the oxygen affinity of hemoglobin, which is essential in enabling hemoglobin to unload oxygen in tissue capillaries. d. oxyhemoglobin (that is, hemoglobin bound to oxygen) and deoxyhemoglobin differ markedly in quaternary structure. e. the affinity of hemoglobin for oxygen depends on ph and co2. both h+ and co2 inhibit the release of bound oxygen.