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General

Wikipedia

http://en.wikipedia.org/wiki/Main_Page

World's Biomes

http://www.ucmp.berkeley.edu/exhibits/biomes/index.php

Biomes

http://www.runet.edu/~swoodwar/CLASSES/GEOG235/biomes/intro.html

Ecosystems

http://library.thinkquest.org/11353/ecosystems.htm

http://www.windows.ucar.edu/tour/link=/earth/ecosystems.html&edu=elem

Arid Environment (Arid Zone)

http://www.fao.org/docrep/T0122E/t0122e01.htm#foreword

Desertification

http://www.fao.org/desertification/default.asp?lang=en

أخبار البيئة

http://www.4eco.com/

CAD, GIS, & GPS Magazine

http://www.cadmagazine.net/maps/index.php

EearthSearch.net

http://www.earthsearch.net/ 

Arab Scientist

http://www.arabscientist.org/?LANG=1