Final answer:
A change in color, shape, taste, and texture that is irreversible typically indicates a chemical change, where the molecular composition of a substance is altered.
Step-by-step explanation:
When observing a substance that has undergone a change in color, shape, taste, and texture, and this change cannot be reversed, we can infer that a chemical change has likely occurred.
A chemical change is characterized by the breaking and forming of bonds between molecules or atoms, resulting in a different kind of matter from the original kind. This process changes the substance's chemical properties and is frequently harder to reverse compared to physical changes.
On the contrary, physical changes do not involve changing the molecular composition and can typically be reversed; they include changes in state, shape, and size but not in chemical structure.
Therefore, if a substance changes in such a way that it cannot go back to its original form and exhibits new properties, it has indeed undergone a chemical change.