Final answer:
Copper is the solid from the listed substances. While water, helium, and air are not solids at room temperature, copper is a metal that remains solid and is copper-colored.
Step-by-step explanation:
The question asks to identify a solid from the given list which includes water, helium, air, copper, and oxygen. Based on the standard states of matter at room temperature, and ignoring any state symbols provided (like water (s) for solid water, i.e., ice), copper is the correct answer as it is a solid at room temperature. In contrast, water and oxygen are liquids or gases depending on the temperature and pressure, helium is a gas, and air is a mixture of gases, primarily nitrogen and oxygen.
The ancient Greeks theorized about matter being composed of elements like earth, air, fire, and water, which they thought corresponded to the states of matter. However, this was a misconception, as the true nature of atoms and elemental states of matter would only be understood centuries later with the advent of improved observational technology.
In summary, copper is a metal with a characteristic copper color and is solid at room temperature. Copper is used in various alloys and as a solvent in solid solutions with other metals.