one of the following is also known as Gardener's best friend.

----------- is found in beaches and river.

Pollution occurs when people release waste, sewage or ______________ into the environment around us.

The leaking or spilling of chemicals or raw sewage into a body of water is ________ pollution.

Soil is formed from all of these natural materials EXCEPT

Plants and animals become part of the soil when they -- 

What is the main source of light of earth?

Light helps us to ….

Light sources that are made/created by humans are called … sources of light.