The human flora is the microrganisms that constantly inhabit the human boy. They include bacteria, fungi and archaea. Some of these organisms are known to perform tasks that are useful for the human host, while the majority have no beneficial or harmful effect. Those that are expected to be present, and that under normal circumstances do not cause disease, are termed normal flora, or microbiota. An effort to better describe the microflora of humans has been initiated; see Human microbiome project.