Apologia Biology: Bacteria

Bacteria:  They are single-celled, very small creatures who obtain their food from where they live, sometimes meaning the anatomy of a homo sapien in order to survive.  Reproduction can take place in the interior or on the exterior of the homo sapien.  Some bacteria inside the body can cause infections.  Conversely, there are also some beneficial bacteria.  These bacteria live in our intestines and put to work the nutrients we eat and the remains will be made into waste.  Also, scientists use some bacteria for vaccines and medicines.