Basically, humans use lot's of energy for heating, lighting, movement, and machines, that energy has come from and energy source. Some sources are renewable, and some are None-Renewable. In general as a Non-Renewable source are fossil fuels. These come from under the ground meaning that there not usable. There can be a fixed amount of coal, oil, and gas in the world and when we use this energy then its gone and there is no coming back.
-Hope this helps .
