As science works, which statements about theories and hypotheses are correct?

• A. A theory is an explanation that suggests the existence of theoretical entities that cannot be measured directly
• B. Theories make predictions about the real world
• C. These predictions become hypotheses that can be tested with experiments and quasi-experiments
• D. All of the above

Answer: (D)

In science, a theory provides a broad, testable framework that explains a wide range of phenomena and often includes entities the theory implies but cannot measure directly; these entities are inferred from indirect evidence and observational data. Theories also make predictions about how the real world should behave under certain conditions. Those predictions are then turned into testable statements—hypotheses—that can be examined through experiments. When true random assignment isn’t possible, researchers can use quasi-experiments to test these hypotheses, still aiming to assess causal relationships. Since each of these aspects—positing unmeasurable but inferred entities, producing real-world predictions, and framing testable hypotheses tested via experiments or quasi-experiments—fits together, all of the statements describe how theories and hypotheses operate in science.