Introduction The body contains bacteria both internally and externally. The human body and some of the bacteria it contains are mutualistic. Mutualism is where bacteria and the host, the human body, benefit from each other and need each other to function. This bacteria is known as the normal microbiota, harmless bacteria available to the body. Still, there are circumstances in which these bacteria can be harmful if they enter unknown tissue through a wound. However, biologists have several reasons to want to know more about these bacteria. The first is to understand the different bacteria present in the body in order to better understand how possible infections can be caused. Second, one must know the native microbes present on any part of the body, which allows doctors to know what to test for. Third, find out what happens when bacteria are present in places where they are not normally found. Finally, educate people about the important role these bacteria play in helping the human body's immune system and protecting itself against other microorganisms. This experiment concerns the isolation of bacteria from the throat, skin and rectum. It is optional. This bacteria will be cultivated in different agar plates. Different agar plates are used for the specific culture. The Snyder test involves seeing if there is a susceptibility to cavities. This test uses saliva and Snyder Ager. Saliva contains bacteria that ferment lactose into lactic acid, which can cause a color change on the agar due to the pH indicator. As for the tomato juice isolation test, it makes it possible to isolate bacteria from normal flora. Using Subouraud agar is a medium that can help detect fungi and yeast cells commonly found in humans. The mouth contains low levels of yeast cells, but having more of them can cause problems in the mouth. This experiment will also use saliva to test microbial diversity in