The door represents the mouth because it opens and closes. In the mouth food is broken down into smaller pieces by teeth and emzymes.
The stomach is simaller to a ball pit because lots of small food pieces are held in the stomach.
The small intestine is simaller to Sponge Bob because the small intestine absorbs nutrience for other parts of the body just like Sponge Bob absorbs water.
A large intestine is like a clogged pipe. a cloged pipe holds solid waste just like the large intestine holds solid waste before it is eliminated. Water is absorbed in the large intestine so that the body does not become dehydrated.