3)ENERGY SOURCES

Energy sources are natural resources that we can use to generate different forms of energy. Then we transform that energy for various purpose.
We can clasify energy sources into two general categories: Renewable and non-renewable.
NON-RENEWABLE ENERGY SOURCES
Non- renewable energy sources come from natural resources that are limited and can be exhausted. At the moment , the most commonly used energy sources are non-renewable. They included fossil fuels(oil, coal and natural gas) and nuclear energy, which uses radioactive materials, such as uranium.


RENAWABLE ENERGY SOURCES
Renawable energy sources come from natural resources that we cannot use up completely. These include hydroelectric, solar, marine, geothermal and biomass resources, as well as energy that we can produce from solid urban waste.