How is a heterogeneous mixture characterized?

A heterogeneous mixture is characterized by a non-uniform distribution of substances, meaning that the different components within the mixture can be easily distinguished and are not evenly distributed throughout the mixture. This can be observed in mixtures such as salad, where you can see and identify the individual components like lettuce, tomatoes, and dressing. The different substances maintain their own properties and can often be separated through physical means, making the distinction evident to the observer.

In contrast, a homogeneous mixture would exhibit a uniform distribution, where the different components are blended so thoroughly that they cannot be easily identified as separate entities. Additionally, a single-phase system refers to mixtures where only one state of matter is present, which does not apply to heterogeneous mixtures that can contain two or more phases. Lastly, a mixture composed only of liquids does not define a heterogeneous mixture, since heterogeneous mixtures can consist of solids, liquids, and gases combined in various ways. Overall, B accurately reflects the key characteristic of a heterogeneous mixture.