Which statement describes commensalism?

Which statement describes commensalism?

• A. One benefits, the other remains unaffected
• B. Both benefit
• C. One benefits, the other harmed
• D. Neither benefits

Answer: (A)

Commensalism is a relationship in which one species gains a benefit while the other is largely unchanged. The benefiting partner might get food, a ride, or shelter, while the host’s health and fitness aren’t noticeably helped or harmed. For example, barnacles attached to a whale ride along to plankton-rich waters, gaining a meal, and the whale isn’t significantly affected. This is different from mutualism, where both benefit, or parasitism, where one benefits at the expense of the other. So the statement that best describes commensalism is that one benefits, the other remains unaffected.

Commensalism is a relationship in which one species gains a benefit while the other is largely unchanged. The benefiting partner might get food, a ride, or shelter, while the host’s health and fitness aren’t noticeably helped or harmed. For example, barnacles attached to a whale ride along to plankton-rich waters, gaining a meal, and the whale isn’t significantly affected. This is different from mutualism, where both benefit, or parasitism, where one benefits at the expense of the other. So the statement that best describes commensalism is that one benefits, the other remains unaffected.