a substance that keeps its shape because its particles can't flow freely is a(n).........

solid

it is a solid because the particles that make up a solid are packed together very tighly so they can not move like particles in liquid.

bill gates

The substance described, which maintains its shape because its particles cannot flow freely, is called a solid. Solids have tightly packed particles that vibrate but do not move freely, preventing them from changing their shape easily. To identify the state of matter, we can consider the characteristics of the substance in question, such as its ability to maintain a fixed volume and shape.