Microbiology is the study of microorganisms that are too small to be seen with the naked eye, including bacteria, archaea, viruses, fungi, prions, protozoa and algae. These microbes play important roles in processes like nutrient cycling, biodegradation, and food production. They can also cause disease but can be harnessed to produce drugs, biofuels, and food through biotechnology. The history of microbiology includes early pioneers in the 19th century like Semmelweis, Snow, and Pasteur who began to understand disease transmission and the role of microbes. Major advances were made in the 20th century with the discovery of antibiotics and the emergence of molecular biology to