Final answer:
Symbiosis encompasses commensalism, mutualism, and parasitism, all forms of close interspecies relationships with varying outcomes for the organisms involved. In mutualism, both organisms benefit, whereas in commensalism one benefits without affecting the other, and in parasitism, one benefits while harming the other.
Step-by-step explanation:
Symbiosis overlaps both commensalism and mutualism, because commensalism and mutualism both involve a close relationship between two species. Symbiosis is a broad term that describes diverse relationships where at least one organism benefits.
Under the umbrella of symbiosis, mutualism describes a relationship where both species benefit, while commensalism refers to a scenario where one species benefits and the other is neither helped nor harmed. Lastly, parasitism is also a form of symbiosis but differs from mutualism and commensalism in that one species benefits at the expense of the other, causing harm.