Which one of the following is popularly known as black gold?

Natural resources should be used

Which resource is used to produce electricity?

Which is most important for the growth of a plant?

 Life is not possible without

The top layer of the earth's surface in which plants grow is

Which one of the following is refined to produce petrol and diesel?

The Exhaustible resources are also known as

The ways to save and collect rain water is known as

Sunlight is an example for