Which observation most likely indicates that only a chemical change has taken place?(1 point)

Question

Responses

A reaction occurs.
A reaction occurs.

The shape changes.
The shape changes.

States of matter changes.
States of matter changes.

The change cannot be reversed.

Answer 1

The observation that most likely indicates that only a chemical change has taken place is:

A reaction occurs.

This is because a chemical change typically involves the transformation of substances and the formation of new substances, which is characterized by a reaction. The other observations, such as changes in shape or states of matter, could also be indicative of physical changes rather than chemical changes.