Final answer:
Kristie used shading to create a natural-looking flush on the face.
Step-by-step explanation:
Kristie drew shading on the face to indicate a natural-looking flush. Shading involves creating variations in darkness or lightness to add depth and dimension to an object or image. In this case, Kristie used slightly darker shading on the cheeks as compared to the chin to create a flushed appearance.
Learn more about Shading in art