Which of the following statements best defines the oxygen-hemoglobin dissociation curve?a) a graphical representation of the amount of oxygen found in the atmosphereb) a graphical representation of the relationship between hemoglobin's percent saturation and the partial pressure of oxygenc) a graphical representation of the amount of hemoglobin found in the bloodd) a graphical representation of the amount of oxygen bound to hemoglobin and how that affects the partial pressure of O2 in the blood