A microbiologist is a scientist who specializes in studying microorganisms, which are tiny organisms that are too small to be seen with the naked eye. These can include bacteria, viruses, fungi and other single-celled living things. Microbiologists use various techniques such as genetic engineering, molecular biology, biochemistry, immunology, virology, parasitology, mycology, and bacteriology to study these microorganisms in order to understand their behavior, interactions with other organisms, and potential applications. They may work in a variety of settings such as research labs, universities, hospitals or pharmaceutical companies, studying the role that microorganisms play in human health, agriculture, food production, environmental science, and biotechnology.