What is the term for a relationship where one species benefits at the expense of another?

• A. Commensalism
• B. Mutualism
• C. Parasitism
• D. Amensalism

Answer: (C)

The term for a relationship where one species benefits at the expense of another is parasitism. In parasitism, the parasite derives nourishment or some other benefit from the host, often harming it in the process. This interaction is characterized by a dependency of the parasite on the host, as it relies on it for resources, while the host typically suffers negative effects such as loss of nutrients, energy, or even death.

In contrast, commensalism describes a relationship where one species benefits while the other is neither helped nor harmed. Mutualism involves both species benefiting from the interaction, and amensalism refers to a situation where one species is harmed while the other is unaffected. Understanding these different types of relationships is essential in the study of ecology and how living organisms interact within ecosystems.