Which statement describes a homogeneous mixture?

• A. Distinct phases, like oil and water
• B. Uniform composition throughout, like saltwater
• C. A mixture that separates into layers over time
• D. A pure substance with fixed composition

Answer: (B)

A homogeneous mixture has a uniform composition throughout. In saltwater, salt dissolves so evenly that any portion has the same salt-to-water ratio, and you can’t see separate parts. If a system shows distinct phases or separations into layers, that’s a heterogeneous situation where the composition isn’t uniform. A pure substance, on the other hand, has a single chemical identity and fixed composition, not a mixture of different substances. So the description that fits a homogeneous mixture is the one with uniform composition everywhere, as seen in saltwater.