Lichens

Lichens are indeed a symbiotic relationship between an "algae" and a "fungus". The "algae" component is typically a green algae or cyanobacteria. This mutualistic partnership allows the fungus to provide a protected environment and nutrients for the algae, while the algae photosynthesize and provide food for the fungus. Therefore, the statement "Lichens are a relationship between an 'algae' and a 'fungus'. The 'algae' is usually a green algae or cyanobacteria" is true.

Through photosynthesis

Identification is usually based on the fungus. This suggests that when it comes to identifying something, such as a species or a sample, the presence or characteristics of a fungus are often used as key indicators. Fungi have distinct features and can be easily observed and analyzed, making them a reliable basis for identification purposes. Algae, on the other hand, may also be used for identification in certain cases, but the question implies that fungus is the more commonly relied upon factor.

They are very sensitive

The statement is true because algae and fungi are often found together in a symbiotic relationship known as a spongy thallus. In this relationship, the algae provide food through photosynthesis, while the fungi provide a protective structure and absorb nutrients from the environment. This association allows both organisms to benefit and thrive in their respective habitats.

Provides protection from harmful light intensities and absorbs nutrients and water
Fungus is usually from the Phylum Ascomycota

Lichens are NOT assigned to a taxonomic group because two different organisms are involved

Fruticose lichen is used by model railroad builders and is usually fed on by Caribou and Reindeer.

Crustose lichens are attached to or embedded in the substrate over the entire lower surface. This means that they are firmly attached to the surface they grow on and cannot be easily detached. They often form brightly colored patches on bare rocks and tree bark, which is a characteristic feature of crustose lichens. This attachment allows them to withstand harsh environmental conditions and provides them with a stable base for growth. Additionally, the fact that they are weakly attached to the substrate suggests that they are not firmly rooted and can be easily detached.

The correct answer states that fruitcose lichens look like miniature shrubs and are usually branched. Additionally, they are attached to the substrate at one point. This means that the lichens have a shrub-like appearance with branches, and they are connected to the substrate at a single point.

Foliose lichens are weakly attached to the substrate and have thalli that are somewhat leaflike in appearance. This means that they are not firmly attached to the surface they grow on and can be easily detached. The thalli, or the leaf-like structures of the lichens, have a similar appearance to leaves, with a flat and lobed shape. This combination of weak attachment and leaf-like thalli helps to distinguish foliose lichens from other types of lichens.