A "zoom" lens has the ability to change its focal length; a "prime" lens does not. Here is a link to my son's incredible Canon EF 24-70mm f/2.8L zoom lens. Here is a link to my incredible Canon EF 50mm f/1.4 lens. In terms of image quality, it is arguable that these two lenses, at 50mm, are quite similar.
So, I prefer primes for the reasons I state here.
The bottom line for me is stated as Image Quality/Price--you can't beat that ratio in primes.