Distinguish between rotation and revolution.

Explain the layers of the earth. Draw a diagram to support your answer.

When it is summers in places in the southern hemisphere, it is winters in the northern hemisphere. Explain, why?

Define solar system. Name the planets of the solar system in the increasing distance from the sun. 

Why is earth the only planet on which life exists?

What are natural satellites?

Name the two factors that are responsible for changing seasons.