This website has information about Desertification including causes, effects, and examples.

Global warming is a problem for the Earth right now and it will continue to be in the future if we don't make a change in our pollution. Burning fossil fuels (which is currently our main source of energy) releases lots of carbon dioxide into the atmosphere. This website presents wind and solar power as environmentally friendly alternatives for sources of energy and gives information on how they can be used.

This website explains information about PCB's, such as where they are found, and presents problems with using them.

This website gives an overview on the uses of DDT, and presents the pros and cons of using it as an insecticide.