The fungi which derive their food directly from dead organic matter are known as

The correct option is Decomposers.

To understand why this is the correct answer, let's look at how different types of fungi obtain their nutrients:
1. Decomposers (Saprotrophs): These are organisms, including many fungi and bacteria, that feed on dead and decaying organic matter. They secrete digestive enzymes externally into the dead material, breaking down complex organic molecules into simpler nutrients, which they then absorb. Since the question asks about fungi deriving food directly from dead organic matter, "Decomposers" is the precise term.
2. Parasitic fungi: These fungi live on or inside another living organism (the host) and absorb nutrients directly from the host's living tissues, often causing harm or disease to the host.
3. Mutualists: These fungi form mutually beneficial relationships with other living organisms. An example is mycorrhizae, where fungi associate with plant roots, helping the plant absorb water and minerals while receiving carbohydrates in return.
4. Predators: Some specialized soil fungi actively trap and consume microscopic living animals (like nematodes) using specialized structures like constricting rings.

Therefore, fungi that obtain their food directly from dead organic matter are classified as Decomposers.