Able to decay naturally and in a way that is not harmful

A gradual increase in world temperatures caused by gases such as carbon dioxide that are collecting in the air around the earth and stopping heat escaping into space

Substances that are used in or produced by a reaction involving changes to atoms or molecules and are harmful for health.

A long period when there is little or no rain

Things such as minerals, forests, coal, etc. that exist in a place and can be used by people

Not harmful to the environment

It is a mixture of solid particles and gases in the air.

The amount used the vital liquid.

The process of getting rid of large amounts of rubbish by burying it, or a place where rubbish is buried

Relating to products, systems, etc. that use as little electricity, gas, etc. as possible