Answer:
Read Carefully.
Step-by-step explanation:
Lichens are considered symbiotic organisms because they result from a mutually beneficial relationship between two different organisms: a fungus and either an alga or a cyanobacterium (or both). This symbiotic relationship is known as mutualism, where both organisms involved benefit from the association.
In the case of lichens, the fungal partner provides a protective structure and obtains nutrients from the surrounding environment. The fungal hyphae create a physical framework that holds the lichen together and provides a habitat for the photosynthetic partner. The fungal partner also absorbs water and nutrients from the environment, which are shared with the photosynthetic partner.
On the other hand, the photosynthetic partner (alga or cyanobacterium) carries out photosynthesis and produces organic compounds through the process. These organic compounds, such as sugars, are then shared with the fungal partner, providing it with a source of energy and nutrients.
The symbiotic relationship allows lichens to thrive in diverse and often harsh environments, including rocky surfaces, tree bark, and even deserts. The fungal partner provides protection and access to nutrients for the photosynthetic partner, while the photosynthetic partner provides a food source for the fungus. This interdependence is the basis of their mutualistic relationship, making lichens a classic example of symbiotic organisms.