Final answer:
Class 3 levers are the most common in the human body, optimizing for range of motion and speed, with the biceps acting on the forearm as an example. The correct option is C.
Step-by-step explanation:
The most common class of levers in the human body is Class 3. In a Class 3 lever, the force is applied between the fulcrum and load. This is seen in the human body where the muscle's force is applied to the bone acting as the lever arm to move a load further away from the pivot point (the joint which acts as the fulcrum). An example of a Class 3 lever in the body is the biceps acting on the forearm to lift an object in your hand.
The efficiency of these levers in generating movement is due to the positioning of the fulcrum, which allows a greater range of movement and speed but often reduces the amount of force that can be applied if compared to Class 1 or Class 2 levers. Since the body often prioritizes range of motion and speed over force, Class 3 levers are ideal for many of its functions.