Answer:
E.
Explanation:
The bird is the simplest machine in the set-up. The bird (E) is using the principle of turning moments. In the principle, the bird balances the other force on the other side of the balance.
It means that the bird, by jumping off the other end of the lever, leaves the force of G, to do the work on the bucket. G does work based on the weight of the items in it.
Therefore, option E is the best answer.
