They occur between organisms of different species. They include protocooperation, mutualism, commensalism and teninism.
It is an association in which one species - the diner - benefits, without causing benefit or harm to the other. The term diner has a more literal interpretation: "diner is one who eats at another's table."
The Remora is a suction cup fish with which it attaches to the shark's womb. Along with the pilot fish, which swims in shoals around the shark, she takes advantage of the food scraps that fall into the mouth of her great "host".
THE Entamoeba coli It is a commensal protozoan that lives in the human gut where it nourishes the remains of digestion.