Which class of organisms primarily consists of decomposers?

The class of organisms that primarily consists of decomposers is fungi. Fungi play a crucial role in ecosystems as they break down organic matter, returning essential nutrients to the soil. This decomposition process is vital for nutrient cycling, allowing nutrients to be reused by plants and other organisms.

Fungi have specialized structures and enzymes that enable them to decompose complex organic materials like dead plants, animals, and organic waste. This function distinguishes them from plants, which primarily produce their own food through photosynthesis, and from consumers, which obtain energy by feeding on other organisms. While producers and consumers perform significant roles in energy acquisition and transfer within ecosystems, it is the fungi that are specifically adapted to the role of breaking down and decomposing organic material, thus playing a unique and essential role in maintaining ecological balance.