Final answer:
As exercise intensity increases, the percentage contribution of anaerobic and aerobic metabolism as an energy source changes. During low-intensity activities, aerobic metabolism is primarily used. However, as intensity increases, both anaerobic and aerobic metabolism contribute to meet the body's demands.
Step-by-step explanation:
The percentage contribution of anaerobic and aerobic metabolism as an energy source changes as exercise intensity increases. During low-intensity activities, the body primarily uses aerobic metabolism and relies on fatty acids as the main energy source. As exercise intensity increases, both anaerobic and aerobic metabolism combine to meet the body's increased demands for ATP production. Anaerobic metabolism becomes more significant, especially for high-intensity activities.