Final answer:
In additive color mixing, red and green forms yellow, and in subtractive color mixing, yellow and blue forms green.
Step-by-step explanation:
In additive color mixing, a combination of red and green forms yellow. This is because red and green are primary colors in additive color mixing, and when combined, they create yellow.
In subtractive color mixing, a combination of yellow and blue forms green. This is because yellow and blue are primary colors in subtractive color mixing, and when combined, they create green.