Microorganisms are tiny organisms that are too small to be seen with the naked eye. They include bacteria, fungi, protozoa, and viruses. Many of these organisms are beneficial to humans and the environment, while some can cause disease. Microorganisms play an important role in the food industry, as they are used to produce fermented foods like cheese and yogurt, as well as breads and alcoholic beverages. They can also be used for bioremediation of contaminated environments.