To make a circle appear to be a sphere in a drawing or painting an artist uses what?

Techniques

Explanation:

To make a circle a sphere, an artist must uses techniques such as cross-hatching and stippling to make the circle look three dimensional. The artist may also use tone to show where the lighting is coming from so it seems more realistic.

:)

toning, shading, cross-hatching

Explanation:

it makes it look more 3D

this exemplifies - rondo form