Fungi is the plural word for "fungus". A fungus is a eukaryotic organism. Yeasts, moulds and mushrooms are examples of fungi. The study of fungi is called mycology. Like animals, humans and most bacteria, all fungi are heterotrophs. Some microscopic fungi, for example yeast, are used in the food and drink industry to produce bread, beer and wine. Fungi are important in the pharmaceutical and biotechnology industries and are used in the production of antibiotics and various enzymes.