Microbiology
Microbiology (from Greek , "mīkros", "small"; , "bios", "life"; and , "-logia") is the study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, parasitology, mycology and bacteriology.
Human interactions with microbes
Microbes can form an endosymbiotic relationship with larger organisms. For example, the bacteria that live within the human digestive system contribute to human health through gut immunity, the synthesis of vitamins such as folic acid and biotin, and the fermentation of complex indigestible carbohydrates. Future drugs and food chemicals may need to be tested on the gut microbiota; it is already clear that probiotic supplements can promote health, and that gut microbes are affected by both diet and medicines.