Answer:
Commensalism: It is a type of symbiotic relationship between two or many individuals where only one species receive benefits and others are unaffected. One partner can live without any help from another partner. Example: Crabs (hermit) using no longer alive gastropods for their protection.
Mutualism: It is a type of symbiotic relationship between two or more species that gets the benefits. Each partner needs another partner for their survival.
Example: Relationship between digestive bacteria and humans.