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

Question

Responses

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

The shape changes.
The shape changes.

States of matter changes.
States of matter changes.

A reaction occurs.

Answer 1

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

A reaction occurs.

Chemical changes involve the formation of new substances and often include reactions between different reactants, which is not the case for mere physical changes.