Final answer:
For a 1500m run, the predominant supplier of ATP is aerobic respiration, as it provides a sustainable energy source required for the duration of the run, unlike creatine phosphate or anaerobic glycolysis which provide energy for shorter periods.
Step-by-step explanation:
The predominant supplier of ATP for a 1500m run is aerobic respiration. During activities like a 1500m run, the muscles require a continuous supply of ATP that is sustained. Creatine phosphate can supply ATP very quickly, but this will only last for about 8-10 seconds. The next phase is anaerobic glycolysis, where glycogen is used to create ATP without oxygen, producing enough energy to last about 90 seconds and resulting in the production of lactic acid. However, given that a 1500m run typically takes around 4-5 minutes, the primary source of ATP will be through aerobic respiration. In aerobic respiration, oxygen is used to break down glucose, which is a slower process but sustainable for the duration required to complete a 1500m run. During this process, the storage form of glucose in muscles, known as glycogen, can also be utilized, providing a prolonged energy source.