Please make sure you are actually asking a meaningful question besides "I need information on X".
WikiPedia,Google,and Yahoo Anshwers should ALL be used BEFORE posting here.
I know, I know, this means you actually need to do some WORK?! and READ?! This isn't a place to just get fed all of the proper answers, you wont have the whole SRL community to help you when taking a test will you?
So please just SEARCH before asking questions.
Good Luck With Your Studies!
<3 YoHoJo