Children's Glossary at Eco-Explorer Kent CC

http://www.naturegrid.org.uk/eco-exp/glossary.html

Atmosphere This is the layer of air surrounding the earth. The two main gases in the atmosphere are oxygen and nitrogen, there are also small amounts of carbon dioxide.
Biodegradable Describes something which will rot naturally through the activity of decay organisms (e.g. decomposers). For example a fallen tree will biodegrade but a plastic bag will not.

Community

The people and groups within an area who have something in common with each other. For example you are part of a school community, but you may also be part of other communities such as a religious group or a neighbourhood group.