As we have studied in Biology class, bacteria are unicellular microorganisms. Which means that bacteria are small, tiny little animals that are literally everywhere in the world. There could be 40 million bacterium in one grain of soil!  

There are a thousands of different types of bacteria in the world that are classified into a few different divisions, parisitism, mutualism, and commensalism.

Parisitism

Parisites use a symbiotic relationship between organisms of different species in which the parasite benefits from a prolonged close relationship with the host, which is harmed.

Mutualism

Mutualist bacteria have a biological interaction with another species, yet unlike parasites, both species benefit from this relationship.

Commensalism

In commensalism two different species share a relationship, but in this relationship one species benefits and the other is neither harmed nor does it benefit.