Which of the following colors is considered a secondary color?

Orange is considered a secondary color because it is formed by mixing equal parts of two primary colors: red and yellow. In color theory, primary colors (red, blue, and yellow) are the foundational colors that cannot be created by mixing other colors. When two primary colors are combined, they produce secondary colors, which include orange, green (from blue and yellow), and purple (from red and blue). This understanding highlights the relationship and interaction between colors in the color wheel, making it essential for estheticians to master color theory for makeup application, skin treatments, and aesthetic practices.