What term describes an explanation that has been repeatedly tested and supported by extensive evidence?

• A. Evolution
• B. Genetic Variation
• C. Mutations
• D. Theory

Answer: (D)

In science, a well-supported idea that has withstood extensive testing is called a theory. A theory ties together many observations and experimental results, helps scientists understand why things happen, and makes predictions that can be tested with new data. Evolution fits this description as a broad framework describing how populations change over time, supported by evidence from fossils, genetics, and observed variation. Genetic variation and mutations are important processes that drive change, but they describe mechanisms, not the label for a tested, evidence-backed idea. So the best term for a repeatedly tested and well-supported idea is theory.