Question

which statement identifies a characteristic of a scientific theory?
it is subjective.
it is a proven fact.
it is based on opinion.
it may change over time.

Explanation:

A scientific theory is an explanation of an aspect of the natural world that is based on a large body of evidence. It is not subjective (as it is based on evidence), not a proven fact (as scientific knowledge is always open - to - revision), and not based on opinion. Scientific theories can change over time as new evidence is discovered. For example, the theory of evolution has been refined over time as new fossil evidence and genetic data have become available.

Answer:

It may change over time.