A curve representing the binding of oxygen to hemoglobin vs. time is called a Hill plot. Whereas a non-allosterically affected enzymatic reaction displays a hyperbolic curve (v0 vs. [S]), a Hill plot shows a sigmoidal curve. This indicates… A) Cooperativity: oxygen-binding to the first of the four Hb subunits helps the binding to the second and so on. B) Antagonism: oxygen-binding to Hb is counteracted by CO2 in the blood. C) There is something wrong here: the binding of oxygen to Hb shows a hyperbolic function. D) I don’t have enough information to come up with an answer. E) Hill had too much time in his hands.