Final answer:
Cardiorespiratory fitness is important because it enhances the efficiency of the heart and lungs, achieved primarily through aerobic exercises that strengthen the heart and improve cardiovascular health.
Step-by-step explanation:
Cardiorespiratory fitness is critical for maintaining a healthy heart and lungs, leading to improved overall health. The best choice among the given options is c) Enhances the efficiency of the heart and lungs. Aerobic exercises, which include activities like cycling, walking, and running, are essential for increasing cardiorespiratory fitness. Regularly performing these exercises can help build up endurance and make the heart stronger, and a stronger heart can pump blood more efficiently throughout the body. Moreover, aerobic exercise boosts the cardiac reserve, the heart's residual capacity to pump blood, and increases the efficiency of oxygen use by the muscles. By improving cardiovascular health, exercise aids in decreasing risk factors for cardiovascular diseases and contributes to better management of cholesterol levels in the body, particularly by reducing low-density lipoproteins (LDLs), which are associated with a higher risk of cardiovascular disease.