Molds (fungi) are heterotrophic organisms that obtain their food from external sources. They are osmotrophic, meaning they absorb nutrients from their surroundings by osmosis. Molds have specialized structures called hyphae, which are thread-like filaments that form a network called a mycelium. The hyphae secrete enzymes into their environment that break down complex organic matter into simpler molecules, which the mold can then absorb.
Molds are important decomposers in the environment, helping to break down dead plant and animal matter and recycle nutrients back into the ecosystem. They also play a role in the production of food, beverages, and medicines, and are used in various industrial processes. Some molds, however, can also cause diseases in plants, animals, and humans.