Answer:
Fungi
Step-by-step explanation:
Fungi is the kingdom including organisms that are eukaryotic (fungi are different from the other two eukaryotic kingdoms: animals and plantae), multicellular (multicellular kingdoms are the same as eukaryotic kingdoms plus some members of the protista kingdom), and heterotrophic, meaning that just like animals, they do not photosynthesize, and do not produce their own food.
Fungi are the main decomposers among all organisms. They have the ability to obtain nutrients from decaying organisms without having to consume the dead matter (unlike detritivores such as worms which also feed from dead matter but have to ingest it fully in order to obtain the nutrients).