Final answer:
The statement about cardiorespiratory fitness being the ability of the heart and lungs to supply oxygen during sustained physical activity is true, emphasizing the role of aerobic exercise in enhancing cardiovascular and muscular endurance.
Step-by-step explanation:
Cardiorespiratory fitness is indeed the ability of the heart and lungs to supply oxygen to skeletal muscles during sustained physical activity. This definition is true and underscores the importance of the cardiovascular and pulmonary systems in physical endurance. During aerobic exercise, such as running, swimming, or cycling, the heart beats faster to pump oxygenated blood to the muscles, increasing the efficiency of the oxygen transport and utilization. Hence, activities that can be maintained over long periods, like brisk walking or medium to long-distance running, are fueled by aerobic metabolism, which relies heavily on oxygen availability. By contrast, anaerobic exercise, exemplified by sprinting, involves short bursts of intense activity where the energy demand exceeds the oxygen supply available, thus primarily relying on energy sources like glucose and not on oxygen transported by hemoglobin and myoglobin.