Parents and teachers have questions about kid's health too. KidsHealth: Parents' Page is the site for you. This also has a tab for teens. So parents come and visit this site together.
A site list of the many body systems for you to investigate. Great information for you here.
Within certain guidelines, ask a scientist anything you want. Teachers - are you a little confused about something you need to teach? You will want to give this a try.
A PowerPoint presentation about the Excretory System.