Which of the following will NOT shift the oxygen dissociation curve to the right?

The oxygen dissociation curve illustrates the relationship between the partial pressure of oxygen and the hemoglobin saturation with oxygen. A rightward shift in this curve indicates a decreased affinity of hemoglobin for oxygen, which facilitates the release of oxygen to tissues.

An increase in pH, which corresponds to a more basic environment (alkaline conditions), stabilizes the hemoglobin structure in a way that enhances its affinity for oxygen. As a result, it does not contribute to a rightward shift of the curve; instead, it tends to shift it to the left. This means that under more basic conditions, hemoglobin holds onto oxygen more tightly, making it less available for tissues.

In contrast, a decrease in pH (more acidic), an increase in temperature, and an increase in CO2 levels all promote a rightward shift of the curve, which helps facilitate oxygen unloading to tissues that are metabolically active and producing acid and heat as byproducts. Thus, the choice that identifies a condition that will not shift the curve to the right is an increase in pH.