Solutions:

The examples of each known class of lever in a human body are :

(i) Nodding of the head is a Class I lever action.

The spine serves as the fulcrum in this situation, with the load at the front and the effort at the back.
(ii) A Class II lever is raising the body’s weight onto the toes. The fulcrum is at the toes on one end, the weight is in the middle, and muscle effort is on the other.
(iii) A Class III lever is one that raises a load with the forearm.

At one end, the elbow joint works as a fulcrum, the biceps exerts the effort in the centre, and the palm is loaded at the other.