A garbage compactor is like the mouth because it crushes and makes things smaller, just like how a mouth crushes and makes food smaller.

A conveyor belt is like an esophagus because it passes things to an area, just like how an esophagus passes food and water to the stomach.

A backpack is like the stomach because a backpack holds the stuff you put in there just like how a stomach holds food and drinks.

A sponge is like a small intestine because a sponge absorbs water just like how VILI in the small intestine absorb nutrients.

A grocery strop is like a large intestine because a grocery store gets rid of the old or spoiled products just like how the large intestine gets rid of waste or indigestible material.

It connects with the muscular system- involuntary muscle in the esophagus which is peristalsis