Final answer:
The statement that a scientific theory is subject to change based on new evidence best describes its characteristic, indicating it is a well-supported explanation that is open to modification with new findings.
Step-by-step explanation:
The correct statement that best describes a characteristic of a scientific theory is: c) A scientific theory is subject to change based on new evidence. This is because a scientific theory is not just a simple guess or an untested hypothesis; it is an explanation of natural phenomena that has been rigorously tested and supported by substantial evidence. It should be noted, however, that scientific theories are not immutable; they can be revised or rejected in light of new evidence or more comprehensive explanations.
A scientific theory therefore is a well-substantiated explanation, being more than just an educated guess. It is an explanation for a set of observations that has been repeatedly confirmed through observation and experimentation. Theories have significant empirical support and are widely accepted within the scientific community, though they remain open to reevaluation as new data emerge.