A set of principles that organizes and explains facts or behaviors is called a theory.

Here's why:

* Organizes facts: Theories provide a framework for understanding a large body of information by grouping related facts and observations.

* Explains behaviors: Theories offer explanations for why things happen, helping us predict future events or behaviors.

* Provides a framework: Theories act as a roadmap, guiding research and investigation into specific areas of interest.

Let me know if you'd like examples of theories in different fields!