Question

most substances that are not metals look dull. why? they are not malleable. they lack luster. they are not ductile.

Explanation:

Luster refers to the way a material reflects light. Metals have high luster and appear shiny, while non - metals generally lack luster and look dull. Malleability (ability to be hammered into sheets) and ductility (ability to be drawn into wires) are not related to the appearance of dullness.

Answer:

They lack luster.