Symbiosis refers to a close and prolonged interaction between organisms of different species. Previously, the term is restricted to a mutualistic relationship wherein both organisms benefit from the interaction. In mutualism, the relationship between the two organisms is interdependent. Each one gains benefits from the other. This type of relationship between different species where both of the organisms in question benefit from the presence of the other. An example is the hermit crab whose shell offers a niche for anemones to exist in which the anemone can defend the crab with its stinging capabilities.