A scientific explanation that has been tested and confirmed is called a "theory." In science, a theory is developed based on a substantial body of evidence and extensive experimentation to explain natural phenomena. Unlike a hypothesis, which is a preliminary idea awaiting testing, a theory has undergone rigorous scrutiny and has consistently withstood attempts at falsification. Scientific theories can evolve or be replaced as new evidence emerges, but they remain well-supported frameworks for understanding the natural world. Examples of well-established theories include the theory of evolution, the germ theory of disease, and the theory of relativity.