which of the following requires the action of a first - class lever in the body? a. jumping b. push - ups c…

Brief Explanations:

In a first - class lever, the fulcrum is between the effort and the load. Nodding of the head involves the atlanto - occipital joint (fulcrum) between the muscles (effort) at the back of the neck and the weight of the front part of the head (load). Jumping involves third - class levers in the legs. Push - ups use third - class levers in the arms. Waving also involves third - class levers in the arm.

Answer:

D. nodding