microbiological relationships

there are 3 types of relationships in the world of microbiology

1) mutualism:
-when both organsims benefit from the relationship

2) commensalism:
-when one organism benefits and the other is neither helped nor harmed

3) parasitism:
-when one organism benefits while the other suffers significant damage

the most common is #3..such is the same in the world we call life =P