You've got a beginner question to ask?, great, you've come to the right place!
But please help us to help you. Please include as much detail as possible, and what you have already done or investigated to find the answer.
Short "How does this work" questions are not proper forum etiquette.
School assignment questions are ok, but show what work you have done already.
Regulars, please be extra nice to beginners asking questions. Do not deride them for anything, if you can't be nice, don't post.