The principles of biology are used daily in the areas of health, hygiene and food preparation, among others. Often, people's everyday applications of biology involve microbes and the control of disease.
One practical application of biology that most people are familiar with is hand washing. Regular washing with soap removes acquired microbes from the skin and helps control the spread of infectious disease. Another application of biology is the set of instructions given to take all of the antibiotic pills in a prescription. If the course is ended early, resistant bacteria survive to add their resistant genes to the next generation. This is the central organizing principle of biology, natural selection, in action.