Final answer:
Decreasing the blood's partial pressure of carbon dioxide at the tissue increases oxygen delivery by reducing hemoglobin's affinity for oxygen and promoting its dissociation, thus releasing more oxygen molecules to the tissues.
Step-by-step explanation:
Oxygen delivery to the body tissues in mammals can be increased by decreasing the blood's partial pressure of carbon dioxide at the tissue. When the level of carbon dioxide in the blood increases, more hydrogen ions (H+) are produced and the pH decreases. This increase in carbon dioxide and subsequent decrease in pH reduce the affinity of hemoglobin for oxygen, promoting dissociation. Thus, more oxygen molecules are released from hemoglobin, increasing the oxygen delivery to the tissues.