Which of the following best describes a heterogeneous mixture?

A heterogeneous mixture is best described as having a distinct separation of different components. In such mixtures, the various substances remain physically separate and can often be observed individually. For example, a salad consisting of lettuce, tomatoes, and cucumbers is a heterogeneous mixture because the ingredients can be seen and distinguished from one another.

This distinction is crucial in understanding mixtures in science. In contrast, the other options describe characteristics of homogeneous mixtures, where the components are uniformly distributed and cannot be easily distinguished. Understanding this difference helps in fields like chemistry and material science, where the behavior and properties of mixtures are important for various applications.