How do you know if an illustration is a pure substance?

Answer 1

An "illustration" is a drawing, it has both material and abstract parts.

Answer 2

An illustration of a pure substance would typically depict a single type of element or compound, without any mixture or impurities present. This could be shown by the absence of different elements or compounds within the illustration, representing a homogeneous substance. Additionally, the labeling or description accompanying the illustration would specify that it represents a pure substance.