Final answer:
Contour lines are used to create form and depth in art. Non-dominant, blind, and blind-dominant contour lines are variations of contour lines that differ in their execution.
Step-by-step explanation:
Contour lines are used to delineate differences in surface features and give flat shapes a sense of form. They follow paths across a shape and can create the illusion of three dimensions.
Non-dominant contour lines are lighter and less defined than dominant contour lines, while blind contour lines are drawn without looking at the paper. Blind-dominant contour lines are a combination of blind and dominant contour lines.