suggestion
Not trying to be mean shendal but you seem to be asking basic questions answered in any amount of basic text books. As a result of blasting an anonymous bulletin board you may not be able to distinguish between good answers and bad answers or even, god forbid, when someone is winding you up. (For example an answerer to an earlier question did not understand "C.I." and I don't mean Chief Instructor). Either that was a classic wind-up or someone was about to give you advice from a standpoint not much clearer than your own. So at the risk of upsetting the apple cart instead of seeking instant answers from unknown sources that may convey a false impression why not invest in a really good book? And study? No one in the business is going to put you down but if you are going to win the hearts and minds of a lot of professional people with 1000's of hours you are going to have to come up with better questions than that. And if you are learning to fly, ask your instructor?