Cardiorespiratory endurance refers to:

Cardiorespiratory endurance is defined as the efficiency of the heart and lungs in supplying oxygen to the muscles during prolonged physical activity. It reflects how well the body can sustain aerobic activity over time. When engaging in exercises that use large muscle groups, a strong cardiorespiratory system enhances performance, allowing individuals to engage in activities such as running, swimming, or cycling with greater stamina and reduced fatigue.

In contrast, the other options focus on different components of physical fitness. For instance, the ability to lift heavy weights pertains to muscular strength, while the capability to perform yoga relates more to flexibility and balance. Flexibility of the muscles is a separate aspect of fitness that does not directly pertain to the efficiency of oxygen delivery and utilization during exercise. Thus, option B accurately characterizes the concept of cardiorespiratory endurance and highlights its importance in overall health and fitness.