Final answer:
Aerobic capacity is best described as the body's ability to withstand fatigue during long-duration activities, utilizing slow-twitch muscle fibers, and is essential for cardiovascular fitness.
Step-by-step explanation:
The best description of aerobic capacity is C) The body's ability to withstand fatigue during long-duration activities. Aerobic capacity is an essential part of cardiovascular fitness and refers to the ability of the heart, lungs, and blood vessels to supply oxygen to the working muscles effectively during extended periods of aerobic activity. Aerobic exercise examples include activities like cycling, swimming, and brisk walking. These activities engage slow-twitch muscle fibers, which are more efficient at using oxygen and can sustain activity for longer periods without fatigue. Therefore, someone with a high aerobic capacity can perform such activities at a moderate intensity for a prolonged time.
Anaerobic exercise, in contrast, involves high-intensity activities that are performed in short bursts. It's associated with building muscular strength, using a higher percentage of fast-twitch muscle fibers, and does not solely rely on oxygen for energy production, unlike aerobic exercises.