Simple, aerobic organisms. Neither bacteria nor plant. Most are poisonous to humans. Thrive in low moisture, low pH environments. Genetic material is bound in a membrane. Have no roots or leaves; contain no chlorophyll; feed off dead organic matter. Approximately 70,000 species exist. Principal commercial use is in food manufacture, in alcoholic beverages, and as antibiotics, like penicillin. Examples are mildew, mold, mushrooms, smuts, toadstools, and yeast. Plural of fungus.