Metabolism stands for the uptake, transport and chemical transformation of substances within an organism as well as the release of metabolic end products into the surroundings. Metabolism serves the build-up and maintenance of the body substance (change in building materials) and energy production (energy metabolism), maintaining proper bodily functions in the process.
Microorganisms (including microbes) are organisms which are normally not visible to the naked eye. In the broadest sense of the word, bacteria, algae fungi and protozoa also belong to this group.
Modeling is implemented in many cases using abstraction processes, in other words by simplification and generalization of real situations. Imitation of a model is not necessarily required in a three dimensional touchable form but can also be achieved using an abstract intellectual operation. Generally valid statements can often be made with the aid of a model.