Which of the following is a physical change that can occur in a substance?

Melting is indeed a physical change that occurs in a substance. During the melting process, a solid transitions to a liquid when it is heated. This change occurs because the particles within the solid gain energy and are able to move more freely, resulting in a change of state without a change in the chemical composition of the substance.

In contrast, burning, rusting, and digestion involve chemical changes. Burning leads to the formation of new substances as materials combust, rusting involves the reaction of metal with oxygen to form rust (iron oxide), and digestion breaks down food into simpler chemical compounds that the body can use. Each of these processes alters the identity and structure of the original material, making them chemical rather than physical changes.