Mutualism:
Mutualism or interspecies reciprocal altruism is a long-term relationship between individuals of different species where both individuals benefit. Mutualistic relationships may be either obligate for both species, obligate for one but facultative for the other, or facultative for both.
Commensalism:
Commensalism describes a relationship between two living organisms where one benefits and the other is not significantly harmed or helped. Commensal relationships may involve one organism using another for transportation or for housing, or it may also involve one organism using something another created, after its death.
Parasitism:
In a parasitic relationship, the parasite benefits while the host is harmed. Parasitism takes many forms, from endoparasites that live within the host’s body to ectoparasites and parasitic castrators that live on its surface and micropredators like mosquitoes that visit intermittently. Parasitism is an extremely successful mode of life.