1) Define energy and its sources.​

Energy is the capacity of a physical system to perform work. Energy exists in several forms such as heat , kinetic or mechanical energy, light, potential energy , electrical, or other forms. Energy is the ability to do work. Energy sources could be classified as Renewable and Non-renewable.

The ability to do work is known as energy. source sun, light, water

world bank is the correct answer.

the density would be a smaller number.