Final answer:
Cutting paper, melting chocolate, and dissolving sugar are examples of physical changes as they only involve changes in form or state without altering the substance at a molecular level. Burning wood is a chemical change since it results in new substances with different chemical properties.
Step-by-step explanation:
Examples of physical changes are processes where the material's properties might change, but its chemical identity remains unchanged. For instance, cutting paper and melting chocolate do not involve a chemical transformation, as the substances maintain their original properties at a molecular level; they are merely changed in form or state. Dissolving sugar in a solution is another physical change because the sugar remains chemically the same and can be retrieved by evaporating the water. However, burning wood is an example of a chemical change, where new substances are formed such as carbon dioxide and water vapor, and the chemical properties of the original material are altered.