My favorite color in the whole world is red. It's the color at the end of the visible spectrum of light.
It red a primary or a secondary color?
It is a primary color in the RGB color model, and it's also in the CMYK color model. It complements cyan. 
Do you know what the color is known to represent?
Well the Ancient Egyptians and Mayans were known to color their faces red for ceremonies, and Roman general would color their bodies when they were victorious. 
I wonder how the use of the color has evolved over the years.
In the Renaissance days it was used on the costumes for nobility and the wealthy, so it seems that it's been around an extremely long time for different uses.