Final answer:
A scientific theory is a well-substantiated explanation for a phenomenon, such as the germ theory of disease, which states that many diseases are caused by microorganisms. It is supported by extensive evidence and scientific testing. Examples include the theory of evolution and cell theory.
Step-by-step explanation:
An example of a scientific theory is the germ theory of disease, which is a well-substantiated explanation for a natural phenomenon. This theory, like all scientific theories, is based on a robust body of evidence that has been repeatedly confirmed through observation and experimentation. The germ theory states that many diseases are caused by microorganisms, a concept that was rigorously tested and validated, providing a foundational understanding of diseases in human biology.
Scientific theories are much more than mere guesses or speculations; they are one of the most certain and reliable forms of scientific knowledge. They are supported by a considerable amount of evidence and have withstood rigorous testing. Other examples of scientific theories include the theory of evolution and cell theory, both of which have drastically shaped our understanding of biology.