Final answer:
A theory is a well-developed set of ideas that proposes an explanation for observed phenomena. Theories are supported by evidence and have been repeatedly tested and confirmed through experiments.
Step-by-step explanation:
A theory is a well-developed set of ideas that proposes an explanation for observed phenomena. Theories are supported by evidence and have been repeatedly tested and confirmed through experiments. They are complex and researchers create hypotheses to test specific aspects of a theory. Theories are a powerful statement in science and explain many observations.