Which statement describes a scientific theory?
a. a theory states how something behaves without explaining why.
b. a theory is a proven fact that cannot be changed.
c. a theory changes based on new observations and testing.
d. a theory is based on a single hypothesis or observation.

Best Answer
C) is the best description, although a scientific theory is not necessarily a "fact". They are, however, based on evidence.

A) is complete garbage.

B) is a good description of a scientific "law"- something that predicts how a certain event will occur without explaining why this is (for instance, the law of gravity accurately describes the gravitational forces between two bodies, but does not explain why these forces are there).

D) is a scientific "hypothesis"- an explanation for an observed phenomena that is yet to be proven.