SIMBIOSIS

is the interactions between different biological species. The symbiotic relationship may be categorized as mutualistic, commensal, or parasitic in nature
Some symbiotic relationships are obligate, meaning that both symbionts entirely depend on each other for survival

Mutualism
Mutualism is any relationship between individuals of different species where both individuals derive a benefit

Commensalism
Commensalism describes a relationship between two living organisms where one benefits and the other is not significantly harmed or helped. It is derived from the English word commensal used of human social interaction.
 
Parasitism
A parasitic relationship is one in which one member of the association benefits while the other is harmed