Using concave mirrors in cooking is one of the benefits of using………………. energy.

Acid rain formed when ………………..combines with rain water.

One of the disadvantages of overusing biofuels is ……………………………….

As the result of global warming the temperature on the earth decreases ................

On burning fuel, we obtain .....................

Coal can be used to produce electrical energy ...................

Fossil fuels were formed under the earth's surface from dead plats or animals after ..................... period of time.

Turbines convert electrical energy into kinetic energy...................

To generate electricity inside electrical power station we need to ............... the fuel.

All of the following are considered as nonrenewable energy resource except...................

Hundreds of years ago people used windmills to crush grain to make flour .................

................ is considered the main source of energy on the earth's surface