An Organism That Lives at the Expense of Another Organism

Question

An organism that lives at the expense of another organism is a _____.
A)mutualistic
B)commensal
C)parasite
D)symbiont

Accepted Answer

A parasite is an organism that lives at the expense of another organism, usually causing harm to the host. Mutualistic refers to a relationship where both organisms benefit, commensal refers to a non-harmful relationship where one organism benefits and the other is unaffected, and symbiont can refer to any relationship where two organisms live together, whether it is harmful or beneficial to either organism.