What is defined as a physical change in the appearance of a material caused by oxygen?

The definition of a physical change in the appearance of a material caused by oxygen aligns perfectly with oxidation. Oxidation is a chemical reaction whereby a substance combines with oxygen, leading to changes in its chemical structure and physical properties. This process is often observable as rusting in metals or browning in fruits, indicating the visible transformation happening to the material.

In contrast, combustion refers to a rapid chemical reaction that produces heat and light, typically involving oxygen, but it encompasses more than just a change in appearance. Corrosion specifically refers to the gradual destruction of materials, often metals, through electrochemical processes involving moisture and environmental elements, not strictly focused on oxygen. Decomposition is the breakdown of substances into simpler components, which may occur without the influence of oxygen.

The unique aspect of oxidation is the direct interaction with oxygen that alters the material's characteristics, making it the most accurate choice for the described scenario.