Sorry, Yusuf:, but this isn't a useful question for this forum. Asking the entire would (we have posters from around the world) of broad expertise (we have high school students, up to people who've been experts in their field for years) to read your textbook for you, and summarize it is simply not doing enough work on your own. You will have to read your own textbook first, then come to this forum for help with specific points you can't understand.
*Topic Locked* and I hope the other noobs see this posting.