A homogeneous mixture that will never settle; the particles are so small they can't be detected by a microscope.

• A. Colloid
• B. Solution
• C. Homogeneous mixture
• D. Pure substance

Answer: (B)

When a mixture is truly uniform and its components are dispersed at such a tiny scale that you can’t see individual particles, and nothing separates into layers over time, you’re looking at a solution. In a solution, the dissolved particles are at the molecular or ionic level within the solvent, so the distribution is even throughout and there’s no settling.

That’s why this description points to a solution: the particles are too small to be detected and won’t settle out, unlike larger particles in a colloid which can be visible under a microscope or cause light scattering, and unlike a general homogeneous mixture or a pure substance, which don’t specifically capture this combination of complete uniformity and invisible particle size.