Name and briefly describe the three types of symbiotic relationships and give an example of each.

• A. Mutualism (both benefit) with example pollinators and flowers; Commensalism (one benefits, other unaffected) with example barnacles on whales; Parasitism (one benefits at the other's expense).
• B. Mutualism (one benefits at the other's expense); Commensalism (both benefit); Parasitism (both harmed).
• C. Mutualism (both benefit) but Commensalism is when both harmed; Parasitism when one benefits only.
• D. Mutualism occurs only in plants; Commensalism only in fungi; Parasitism only in bacteria.

Answer: (A)

Symbiotic relationships are interactions where two species live in close association. The three types are mutualism, commensalism, and parasitism. In mutualism, both partners benefit—for example, pollinators like bees gain nectar, and flowers get helped with pollen transfer, helping both species reproduce. In commensalism, one benefits while the other is largely unaffected; an example is barnacles attaching to whales, which helps the barnacles but doesn’t noticeably help or harm the whale. In parasitism, one benefits at the expense of the other; a parasite such as a tick or tapeworm gains nutrients while the host can be harmed or weakened.

This is the best description because it matches how these relationships are defined and gives clear, typical examples for each type. Other options mix up who benefits or suggest these relationships only occur in certain organisms, which isn’t accurate—these interactions happen across many kinds of organisms, not just plants, fungi, or bacteria.