What type of relationship is characterized by one species benefiting while the other is neither helped nor harmed?

The correct answer is commensalism. This type of relationship is defined by the way one species derives benefit from the interaction while the other species remains unaffected, which means it neither gains anything nor suffers any detriment. An example of this could be barnacles adhering to a whale; the barnacles benefit by gaining access to nutrient-rich waters as the whale moves, while the whale is largely unaffected by their presence.

In contrast, mutualism involves both species benefiting from the interaction, such as flowering plants and their pollinators. Competition refers to the interaction where two or more species vie for the same resources, ultimately leading to negative effects on both parties involved. Predation is a relationship where one species (the predator) benefits by consuming another species (the prey), which is harmed or killed in the process. Thus, the emphasis on the one-sided benefit in commensalism differentiates it from these other types of interactions.