The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
Humans have been polluting the earth and changing the delicate balance of nature. If this trend continues the earth as we know it will be destroyed. If we want to continue to have a green earth, we need to work towards it. Education is the first step in that direction.This glossary will be a valuable resource for you in that endeavor. It is searchable and you can share definitions on your facebook page.