Symbiosis: interaction between two different organisms living in close physical association, typically to the advantage of both.
mutualism: the doctrine that mutual dependence is necessary to social well-being.
Commensal: an association between two organisms in which one benefits and the other derives neither benefit nor harm.
Parasitism: is a non-mutual symbiotic relationship between species, where one species, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred primarily to organisms visible to the naked eye, or macroparasites