Wherever you look there is always a ecosystem. The organisms that are near your house are anything from trees, grass, flowers, etc. There is also dirt, it may look like nothing but there tiny microscopic organisms that live there. Insects are highly involved in an ecosystem, you got spiders, ants, bees, flies, worms and etc. Basically anything you can think of is in an ecosystem.
Acids break down the sandwich and it goes into the intestines and the enzymes and bacteria break it down more then it is absorbed into the intestines through the body.
