whats a good analogy for a digestive system?

Question

an exapmle for an immune system would be like an army, because it fights stuff. but i need one for digestive system. any ideas?

Answer 1

I used to use an analogy of the digestive system compared to the automobile. The gas that goes into the car is the food. The gas tank is our stomachs where the gas is stored until its used. Then it goes out of the tail pipe smelling stinky just like when it comes out of our bodies.

Answer 2

how about a garbage treatment/ recycling facility.
the new garbage material is shreded and put into a conveyor. workers pick off the valuable recycleable material like paper, steel, aluminum and plastic. this is like the intestines leeching off nutrients from your food.
then what can't be used, is sent out to the 'dump'

Answer 3

Membrane for skin. You can also write how we are pretty much a universe inside of a universe inside of another universe. Atoms and molecules make up the cells of the cell, cells make up the biological body, biological bodies are the cells of this celestial objects, central objects at just cells of the galaxy, galaxies are just cells of the universe, ect...