You should add Manjaro as a derivative of Arch.
You also need to seperate the other distros from "Variants of ubuntu" it looks like you marked OpenSUSE, Fedora etc as variants of ubuntu when they arent. If you put Xubuntu you might as well also add Lubuntu and Kubuntu. Also, this is my second edit, you really suck at creating descriptions for distors, As for the description of linux itself, its not an OS. Linux is just the kernel and then there are free operting systems that use it as a base known as GNU/Linux.