Explain the differences between the three classes of levers in terms of the location of the fulcrum, input force, and output force or load. A first-class lever: fulcrum is between input and output force; second-class lever: output force is between input force and fulcrum; third-class lever: input force is between fulcrum and output force. B second-class lever: fulcrum is between input and output force; first-class lever: output force is between input force and fulcrum; third-class lever: input force is between fulcrum and output force. C third-class lever: fulcrum is between input and output force; first-class lever: output force is between input force and fulcrum; second-class lever: input force is between fulcrum and output force. D third-class lever: fulcrum is between input and output force; second-class lever: output force is between input force and fulcrum; first-class lever: input force is between fulcrum and output force.