What act as decomposers and consume dead organisms.

fungi and detritivores,

Explanation:

fungi along with invertebrate organisms sometimes called detritivores, which include earthworms, termites, and millipedes. ... While decomposers break down dead, organic materials, detritivores—like millipedes, earthworms, and termites—eat dead organisms and wastes.

some fungi obtain their nutrients from a living host (plant or animal) and are called most biotrophic fungi have fairly narrow host ranges—they are specialized on a limited called rhizomorphs that allow the fungus to grow from one tree to another. ascospores are formed inside a sac-like structure called an ascus. so your answer is a