What's the difference between CMYK and RGB?

Q4.What’s the difference between CMYK and RGB?

CMYK (Cyan, Magenta, Yellow, and Key [Black]) are the colors we use in the printing process. RGB (RGB) are the colors used in monitors and screen displays. Create your document in CMYK mode so that the colors on your screen match as closely as the final printed product. Printing in RGB could result in color variation.