The correct answer is (b). Lichens are a symbiotic association of algae and fungi. The algae provide the fungi with food, while the fungi provide the algae with protection and a place to live. Lichens are able to grow in harsh environments, such as on bare rocks, because they are able to photosynthesize. This means that they can make their own food from sunlight, water, and carbon dioxide. Lichens are an important part of the environment because they help to break down rocks and release nutrients into the soil. They also provide food and shelter for other animals.
Option (a) is incorrect because bacteria are not involved in the formation of lichens. Option (c) is incorrect because fungi and bacteria are not able to form a symbiotic relationship. Option (d) is incorrect because mosses are not able to photosynthesize.