University of Hamburg
University of Hamburg: Symbiosis & Normal Microbiota
A diagram of the different types of symbiosis. There are 4 examples of symbiotic relationships and explanations. Read this page and then give yourself a quiz.
Biology Pages
Kimball's Biology Pages: The Human Gastrointestinal (Gi) Tract
This site provides an in-depth look at the human gastrointestinal tract.
Wikimedia
Wikipedia: Gastrointestinal Tract
Wikipedia provides excellent resources and information on the gastrointestinal or digestive tract, including images and hyperlinked terms.
Inner Body
Innerbody: Digestive System
Take a look inside the human body's digestive system. This site features diagrams of the digestive tract and each part is accompanied by labels and descriptions. Just select an organ by moving the mouse over its image.