What is an example of mutualism?

Mutualism is a biological interaction where both parties involved benefit from the relationship. In the case of lichens, they are formed from a partnership between a fungus and a photosynthetic microbe, such as algae or cyanobacteria. The fungal partner provides structure, protection, and moisture, while the photosynthetic microbe produces food through photosynthesis, benefiting the fungus. This interdependent relationship exemplifies mutualism as both organisms thrive through their collaboration, making option B the clear representation of this concept.

Other responses discuss relationships that do not meet the criteria of mutualism. For example, while lichens consist of two different organisms, the choice labeling them as merely an "association" lacks specificity regarding their mutual benefits. The mention of a symbiotic relationship between two animals might suggest a mutualistic interaction but does not provide enough detail to confirm mutual benefits. Additionally, a predator-prey relationship involves one party benefiting at the expense of the other, which is not mutualism at all.