How long will the aerobic system provide energy for physical activity?

The aerobic system is designed to provide energy for extended periods during physical activity via the breakdown of carbohydrates and fats in the presence of oxygen. This system can continue supplying energy as long as there are adequate nutrients available, such as glucose and fatty acids, for sustained aerobic metabolism. This means that the duration for which the aerobic system can effectively provide energy is not limited to a specific time frame like the other options suggest, but rather contingent on the availability of these nutrients within the body.

In contrast, the other options indicate set time limits for energy provision. The specificity of 5 hours, 2 hours, or 60 minutes does not encapsulate the true nature of the aerobic system, which can function efficiently for as long as the body has the necessary fuel sources. This flexibility makes the aerobic system ideal for endurance activities, where the duration of energy production can greatly exceed what is indicated in those choices.