Fungi are a diverse group of plants that are not capable of photosynthesis but obtain carbon nutrition from the absorption of carbon compounds from the environment. The group includes organisms ranging from yeast to moulds to mushrooms and organisms that have broad ability to degrade complex organic molecules in the environment.
Fungi are responsible for the spoiling of food (mouldy bread) and rotting of wood and may be useful in the biological oxidation of toxic and hazardous substances such as certain chlorinated hydrocarbons. Fungi are important in the release of spores into the atmosphere, thereby contributing to indoor air pollution, sick-building syndrome, and allergic responses termed hay fever. Most fungi require oxygen in the air for growth. A few fungi can cause infectious diseases in humans.