Mold is a type of fungus that grows on organic matter in moist and shady conditions. It can be found both indoors and outdoors, and it plays an important role in decomposing dead plants and animals. However, mold can also cause problems for human health and property, especially when it grows in large amounts or produces toxins. It can be identified by its fuzzy or dusty appearance, and by the spores it releases into the air. Spores are microscopic cells that help mold reproduce and spread. Some spores are colored, while others are invisible to the naked eye. To see the spores and the structure of mold, one needs to use a microscope. Under a microscope, mold looks like a network of thin, branching filaments called hyphae. Hyphae form a mass called a mycelium, which is considered a single organism. At the tips of some hyphae, mold produces spores in different shapes and sizes, depending on the species of mold.