Which of the following is a key component of fitness?

Cardiovascular endurance is considered a key component of fitness because it focuses on the efficiency of the heart, lungs, and circulatory system during prolonged physical activity. It is indicative of a person’s overall aerobic fitness and ability to sustain exercise over time. Improving cardiovascular endurance has significant health benefits, including better oxygen delivery to muscles, enhanced stamina, and a reduced risk of chronic diseases such as obesity, diabetes, and heart disease.

While the other options like body composition, muscle power, and agility are also important aspects of physical fitness, they represent different facets of overall fitness. Body composition pertains to the ratio of fat to lean mass in the body, muscle power relates to the ability to exert force quickly, and agility refers to the ability to change direction quickly and effectively. Although vital for various activities and sports performance, cardiovascular endurance is foundational because it supports a high level of performance across all physical activities and is crucial for maintaining overall health and fitness.