A type of green algae grows on a type of fungus in the natural in the state of mutualism. Explain the relationship between these organisms.

Mutualism is a close interaction within ecology, from which both organisms have a certain advantage. Mutualism is usually not necessary for the organisms, and the relationship is often short-lived. An example is the cohacks (birds), which occasionally use larger ruminants as a pantry. Both parties benefit from the birds eating parasites in the ruminant's skin, but they are not dependent on it.

Dead plant materials such as leaf litter and wood, animal carcasses, and feces. They perform a valuable service as Earth's cleanup crew. Without decomposers, dead leaves, dead insects, and dead animals would pile up everywhere.