Which branch of science focuses on microorganisms?

Microbiology is the branch of science that specializes in the study of microorganisms, which include bacteria, viruses, fungi, and protozoa. This field encompasses their physiology, genetics, ecology, and their interactions with humans, animals, plants, and the environment. Microbiologists conduct research to understand the role of these microorganisms in various biological processes, their potential benefits, and their capacity to cause diseases.

While the other areas listed, such as virology, biochemistry, and immunology, focus on specific aspects related to microorganisms, they do not have the same broad scope. Virology specifically addresses viruses, biochemistry looks at the chemical processes within and related to living organisms, and immunology studies the immune system, including how it reacts to pathogens like viruses and bacteria. Thus, microbiology stands out as the comprehensive discipline dedicated to exploring the vast world of microorganisms, making it the most accurate answer to the question.