Confused on what action the checkmark would cause.

In FireFox 15.0.1, under "Tools", "Clear Recent History"... a "Clear All History" window opens. I'm confused as to which items I should have checkmarks on.

I would really really appreciate, if someone has the time, if they would give me just a quick "dummies" notes on each, what each would do if I checkmarked that particular item. I'm using a personal computer at home.

(In brackets below, I've jotted down what I think some mean. A couple of them seem like the same thing to me. Please correct me).

I should know this stuff by now, never really took notice of a couple of them.
Thank you so very much!

- Browsing & Download History
- Form & Search History
- Cookies (tracking)
- Cache (do this after banking... but sounds like the same as "browsing and download history option?)
- Active Logins (will this log me out of forums?)
- Offline Website Data (?)
- Site Preferences (?)

 

http://www.firefoxfacts.com/2008/12/12/how-to-clear-private-data-in-firefox/ should give you the basics...