Which characteristic best describes class 2 levers?

Class 2 levers are characterized by the position of the resistance being located between the effort and the fulcrum (axis of rotation). This configuration allows for a mechanical advantage, meaning that a smaller effort can move a larger resistance. In this type of lever, the effort arm is indeed longer than the resistance arm, which is crucial because it allows the effort applied to be amplified when moving the resistance. This characteristic is utilized in various activities and anatomical structures within the body, such as standing on tiptoes, where the calf muscles exert force to lift the body against gravity.

The other options, while they relate to lever systems, do not accurately describe the fundamental characteristics of class 2 levers. The placement of resistance, effort, and fulcrum in class 2 levers is what makes them distinct and effective for generating torque in physical activities. Thus, option A succinctly captures the defining feature of this lever class.