Which type of symbiotic relationship benefits both species?

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

Answer: (D)

Mutualistic relationships are when both species gain something from interacting. This is why it’s the best choice: in mutualism, the partnership improves each participant’s survival or reproduction. For example, bees get nectar from flowers, while they help flowers reproduce by pollinating them. In the human gut, helpful bacteria digest certain foods and produce vitamins, and in return the bacteria receive a nutrient-rich environment. Contrast that with other types: commensalism benefits one partner while the other is largely unaffected; parasitism benefits one at the expense of the other; predation involves one organism killing and consuming another, not a mutual benefit. So only mutualism results in benefits for both species.