Answer:
the correct answers are C and D: "<em>Both partners are able to grow on substrates on which each would not be able to grow on their own</em>", and "<em>The fungi receive carbohydrates and, in some cases nitrogen, from the algae, while the algae gain a "home" that anchors them on the substrate</em>".
Explanation:
Lichens are the result of a symbiotic association between algae and a fungus. These two organisms must cooperate to survive in places under certain inhospitable conditions, where otherwise, they would not be able to survive by themselves. Algaes are the photosynthetic organisms that provide carbohydrates to fungus. These last ones, get the carbon and energy they need to grow, and in exchange, they protect the algae from dehydration and radiation, and they might also provide minerals for their survival. Algae can also get a way to get attached to the substrate. When instead of regular algae, there is a prokaryotic cyanobacterium, these can also supply with fix nitrogen to fungus, in the form of nitrogenous compounds.
