Lichens are a mix of two organisms—a fungus and an alga. The alga, by virtue of its ability to carry out photosynthesis, provides food for the fungus. The fungus, in turn, protects the alga by forming a covering over it. What kind of an interaction is being exhibited by the fungus and the alga? A. Commensalism B. Mutualism C. Competition
This type of relationship is where all organisms involved benefit from the interaction. The relationship can be obligatory (where the organisms cannot live independent of each other) or can be facultative (where they can also live independent of each other). In lichen, this relationship is facultative.
