Which observation most likely indicates that only a chemical change has taken place? A. states of matter changes. B. the change cannot be reversed. C. the shape changes. D. A reaction occurs.

Answer 1

The observation that most likely indicates that only a chemical change has taken place is D. A reaction occurs.

Chemical changes typically involve a reaction that results in the formation of new substances, which is distinct from physical changes that may alter the form or state of a substance but do not produce new chemical substances.