Which pairing correctly matches a symbiotic relationship?

• A. Parasitism: bees and flowers; commensalism: barnacles on whales; mutualism: tapeworms in intestines.
• B. Mutualism: bees and flowers; commensalism: barnacles on whales; parasitism: tapeworms in intestines.
• C. Mutualism: barnacles on whales; commensalism: bees pollinating flowers; parasitism: tapeworms in intestines.
• D. Mutualism: tapeworms in intestines; commensalism: barnacles on whales; parasitism: bees and flowers.

Answer: (B)

Understanding symbiotic relationships means recognizing how species interact and whether both benefit, one benefits and the other is harmed, or one benefits while the other is unaffected. In a mutualism both species gain: bees get nectar and pollen while flowers get pollinated, so bees and flowers are a classic mutualism. In commensalism one species benefits and the other is largely unaffected; barnacles attaching to whales gain a surface to live on and access food, while the whale isn’t helped or harmed in a meaningful way. In parasitism one organism benefits at the expense of the other, as tapeworms in the intestines absorb nutrients from the host and can cause harm.

Therefore, pairing mutualism with bees and flowers, commensalism with barnacles on whales, and parasitism with tapeworms in intestines correctly matches the typical examples.