Commensalism

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A titan triggerfish (Balistoides viridescens)

In ecology, commensalism is a class o relationships atween twa organisms whaur ane organism benefits frae the ither wioot affectin it. This is in contrast wi mutualism, in which baith organisms benefit frae ilk ither, amensalism, whaur ane is harmed while the ither is unaffectit, an parasitism, whaur ane benefits while the ither is harmed.