Final answer:
Color theory is vital to effective makeup applications as it helps makeup artists understand how colors interact and how to create harmonious color combinations.
Step-by-step explanation:
The subject vital to effective makeup applications is Color theory. Color theory is the study and application of color and how colors interact with each other. It helps makeup artists understand how to create harmonious color combinations, choose the right foundation shade for a person's skin tone, and enhance features using different shades and tones.
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