Final answer:
The affinity of hemoglobin for O2 is decreased in rapidly metabolizing tissues.
Step-by-step explanation:
The affinity of hemoglobin for O2 is decreased in rapidly metabolizing tissues. This statement is true. Rapidly metabolizing tissues, such as muscle, have a higher demand for oxygen. As a result, the partial pressure of oxygen in these tissues decreases, which leads to a decrease in the affinity of hemoglobin for oxygen. This allows more oxygen molecules to dissociate from hemoglobin and enter the tissues, meeting their oxygen demands.