What is NOT a characteristic of a solution?

The correct answer identifies a characteristic that does not apply to a solution. Solutions are homogeneous mixtures where the solute is completely dissolved in the solvent, creating a single phase. One of the defining features of a solution is that its components cannot be separated by filtration. This is because, in a solution, the solute particles are at the molecular or ionic level and are too small to be captured by filtration, which is typically used for mixtures like suspensions or colloids where larger particles are present.

In contrast, the other characteristics mentioned support the definition of a solution. A solution is indeed homogeneous, indicating that it has a uniform composition throughout. Solutions typically remain stable over time, meaning that the solute does not settle out or separate from the solvent under normal conditions. Therefore, the ability to filter components would contradict the essential properties of a solution, making it the correct choice for what is NOT characteristic of a solution.