Final answer:
The most beneficial physical activity for improving cardiovascular and muscle endurance is a combination of moderate to vigorous aerobic activity and high-intensity interval training, which enhances heart and lung strength as well as muscular endurance.
Step-by-step explanation:
For individuals aiming to improve heart and lung strength as well as cardiovascular and muscle endurance, the most beneficial type of physical activity would be D. A combination of moderate to vigorous aerobic activity and high-intensity interval training.
Aerobic exercises are those in which the body's large muscles move in a rhythmic manner for a sustained period, and they are particularly effective at enhancing cardiovascular health and muscular endurance. Such exercises include activities like cycling, swimming, brisk walking, and running. When performed at a moderate to vigorous intensity, they can significantly strengthen the cardiac muscle, promote efficient oxygen use by the muscles, and improve endurance.
Moreover, incorporating high-intensity interval training (HIIT), which includes short bursts of very high-intensity anaerobic exercises alternated with recovery periods, can further enhance cardiovascular fitness and muscle strength. HIIT helps push the cardiovascular system to adapt and improve its capacity, offering a comprehensive workout that benefits both the heart and lungs and muscle endurance.