Final answer:
When a salad dressing is changed, the new dressing typically comes on the side, allowing the customer to add it as they wish; this is often how restaurants handle dressing changes. Chemically, salad dressings can exemplify heterogeneous mixtures, which do not have a uniform composition.
Step-by-step explanation:
When a customer opts to change the dressing on a salad, it's typical for restaurants to accommodate this by providing the chosen dressing on the side. This way, the customer can add the amount of dressing they prefer to their salad. However, this question appears to be hypothetical and might not reflect the policies of all dining establishments. The context may refer to the concept of mixtures in chemistry, where salad dressing can be seen as a heterogeneous mixture, like oil and vinegar, whose composition is not uniform. In contrast, a commercial sports drink is an example of a homogeneous mixture with uniform composition throughout.