Which term is a well-supported explanation that explains a group of facts?

• A. Law
• B. Metabolism
• C. Isotonic
• D. Theory

Answer: (D)

In science, a theory is a well-supported explanation that ties together a group of related facts and observations. It isn’t just a guess; it’s a framework that explains why things happen and makes testable predictions that researchers can check with evidence. That’s why this term best fits the idea of a well-supported explanation for a set of facts.

By contrast, a law describes what happens—an observed pattern—without necessarily explaining why it happens. Metabolism refers to the chemical processes inside living things, and isotonic is a term describing equal solute concentration in solutions, neither of which provide the broad explanatory framework that a theory does.