What is shown by making light and dark parts on a sphere?

Correct answer: Roundness and volume

Direct answer: C, roundness and volume. A sphere is a three-dimensional form, but a drawing on paper is usually flat. To make the viewer understand that the flat circle represents a rounded solid object, the artist changes the value from light to dark. The light area suggests the part facing the light source, the middle value shows the turning surface, and the dark area suggests the shaded side. These gradual value changes create the visual impression of curved form and volume. A is wrong because value does not merely name a colour; it describes how light or dark it is. B is wrong because a flat shape has only height and width, while shading makes it appear three-dimensional. D is wrong because paper thickness is a physical property of paper, not an effect produced by shading a sphere. Memory cue: value gives a flat shape the feeling of form.