Imagine having this.

Artists best achieve contrast in a composition by: a. drawing with realism b. shading a drawing with dark and light values c. using drawing techniques like stippling and hatching d. focusing on line and shape in a drawing

This medium typically is made of graphite, a crystalline form of carbon:

Behaviorists focus on behaviors that.. a are observable b are caused by unconscious desires and conflicts c people become consciously aware of d can be categorized into a theoretical system