Answer:
The correct answer would be commensalism.
Commensalism is a type of symbiotic relationship between two organisms or different species in which one organism is benefited and other is neither harmed nor benefited.
Commensal is the termed used for the organism that is benefited.
The commensal may obtain shelter, nutrition, locomotion, or support from the host species without affecting it.
Commensalism usually develops between a small commensal and a large host.
For example, remora rides attached to larger fishes and sharks, birds make nests in large trees, imperial shrimp rides on sea cucumbers et cetera.
