What type of symbiotic relationship benefits one organism while harming another?

The correct answer is parasitism. In this type of symbiotic relationship, one organism, the parasite, benefits by deriving nutrients at the expense of the other organism, known as the host. The parasite often lives on or inside the host and can cause harm, which may range from mild discomfort to severe health issues or death for the host. This distinct relationship is characterized by the fact that the parasite is dependent on the host for survival, but the host suffers negative effects as a result.

Commensalism, on the other hand, involves one organism benefiting while the other is neither helped nor harmed. Mutualism is when both organisms benefit from the relationship. Symbiosis is a broader term that encompasses various types of interactions, including mutualism, commensalism, and parasitism. Understanding these definitions helps clarify the unique nature of parasitism as one party thrives at the expense of the other.