Question

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

The change cannot be reversed.
The change cannot be reversed.

States of matter changes.
States of matter changes.

The shape changes.
The shape changes.

A reaction occurs.

Answer 1

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

**A reaction occurs.**

This suggests that new substances have formed, which is characteristic of a chemical change.