Final answer:
An actively contracting muscle causes the oxygen-hemoglobin saturation curve to shift to the right, meaning that hemoglobin has less affinity for oxygen under conditions of increased temperature and decreased pH.
Step-by-step explanation:
The question relates to the effect of local conditions in actively contracting muscles on the oxygen-hemoglobin saturation curve. When muscles contract, they generate heat and produce acidic molecules, causing a local increase in temperature and a decrease in pH levels. This results in the production of carbon dioxide in the blood, which reacts with water to form bicarbonate and hydrogen ions. As carbon dioxide levels rise, the pH drops, and hemoglobin's affinity for oxygen decreases, causing the oxygen to dissociate from hemoglobin. Consequently, the oxygen dissociation curve shifts to the right, indicating that more oxygen is required to achieve the same level of hemoglobin saturation. This shift to the right enhances oxygen delivery to active tissues.
The main answer to the student's question about the shift of the oxygen-hemoglobin saturation curve due to warmth and lower pH caused by actively contracting muscle is: D. Right; less.