Over the last 30 years man-made CFCs have been the main cause of stratospheric ozone depletion. CFCs however, are not the only ozone-depleting chemicals. Other ODCs include the methylhalides, carbon tetrachloride (CCl4), carbon tetrafluoride (CF4), and the halons which contain bromine instead of chlorine.
Part of the Internet applications glossary: Yahoo! is an Internet portal that incorporates a search engine and a directory of World Wide Web sites organized in a hierarchy of topic categories.
The definition of a search engine is a computer program used to find specific websites on the Internet or to find desired information on the Internet. Google is an example of a search engine. software designed to examine documents, websites, etc. in order to locate items on a specified topic or having a given property.