What characterizes a parasitic relationship?

A parasitic relationship is characterized by one species benefiting at the expense of another. In this type of interaction, the parasite derives nourishment and possibly other benefits from the host species, which is harmed in the process. The parasite exploits its host for resources such as nutrients, shelter, or reproductive opportunities, ultimately leading to potential harm, suffering, or even death of the host organism. This relationship is a key component of ecological dynamics, illustrating how organisms interact within ecosystems.

In contrast, mutualistic relationships are those where both species involved benefit, while commensalism describes situations where one species benefits and the other is neither helped nor harmed. Competition reflects scenarios where two organisms vie for the same limited resources, but this does not inherently involve a parasitic dynamic. Thus, the correct characterization of a parasitic relationship aligns with the idea of one species gaining an advantage at the cost of another.