Which of the following describes a suspension?

• A. Suspension
• B. A heterogeneous mixture that separates into layers over time
• C. A pure substance
• D. A pure element

Answer: (B)

A suspension is a heterogeneous mixture where the dispersed particles are large enough to be seen and will settle out of the liquid over time, forming a distinct layer. This settling happens because gravity pulls the particles down, so when you let a muddy water or sand-in-water mixture stand, the solid particles separate from the liquid. This behavior—being a mixture with visible particles that separates into layers over time—is what defines a suspension. It’s different from a pure substance or a pure element, which have uniform composition throughout, and it isn’t just a restatement of the word “suspension.”