What defines a scientific theory?

A scientific theory is characterized as a well-tested explanation for observations that has been repeatedly validated through extensive evidence and experimentation. This definition underscores the rigorous nature of scientific inquiry; theories are not merely speculative ideas but are grounded in systematic research that supports their validity.

Theories are formed through the accumulation of data and understanding gained from various experiments and observations. They are dynamic and can be refined or disproven as new evidence arises, which is a crucial aspect of the scientific method. This differentiates them from mere guesses or untested hypotheses, which lack the robust support of empirical data that theories possess.

In contrast, the other options represent concepts that do not meet the criteria of a scientific theory. A random guess lacks any systematic investigation, an untested hypothesis has not yet undergone experimentation to validate its claims, and a collection of unrelated facts does not offer a cohesive explanation or framework for understanding a particular phenomenon. Thus, the accurate characterization of a scientific theory as a well-tested explanation is essential for grasping the nature of scientific knowledge and its development.