What is the term used to describe the strength a body needs to function and sustain physical and mental activities?

The term that describes the strength a body needs to function and sustain physical and mental activities is "energy." Energy is fundamental to all biological processes and is derived from the nutrients we consume, such as carbohydrates, fats, and proteins. It powers daily activities, keeps essential bodily functions running, and supports both physical exertion and mental focus.

While stamina, vitality, and endurance are often associated with the body's ability to perform tasks over time, they do not encapsulate the overall requirement of energy as comprehensively. Stamina typically refers to the ability to sustain prolonged physical or mental effort, and endurance relates to the capability to withstand fatigue during physical exertion. Vitality, on the other hand, conveys a sense of lively energy or vigor but is not the technical term that encompasses the total energy needed for bodily function. Therefore, energy is the most appropriate term to describe the strength required for both physical and mental activities.