What types of non-living organic material do fungi decompose?

Fungi primarily decompose non-living organic materials such as dead plant matter, including leaves, wood, and root systems. They also break down animal remains, including carcasses and excrement. Additionally, fungi play a crucial role in the decomposition of complex organic compounds, such as lignin and cellulose, which are found in the cell walls of plants, thereby contributing to nutrient cycling in ecosystems.