Which statement describes mutualism?

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

Answer: (C)

Mutualism is when two species interact and both gain something from the relationship. For example, bees collect nectar from flowers and simultaneously help the flowers reproduce by spreading pollen. In the gut, certain microbes help us digest food and, in return, they receive a place to live and nutrients. In coral reefs, algae inside coral tissues perform photosynthesis and share the sugars with the coral, while the coral provides a protected environment and nutrients for the algae. Because both sides benefit, this is mutualism. Other relationships describe situations where only one partner benefits (parasitism) or where one benefits while the other is unaffected (commensalism), or where neither gains from the interaction.