"Linux" did not add the color option to ls. It an option of GNU-ls (GNU coreutils). You can install/compile it on Unix systems too (as I usually do). Same for bash,grep,... Has nothing to do with Linux per se.
What does it mean "introduced concepts like multitasking, multiuser capabilities, ..."? UNIX by no means "introduced" any of this. Multiuser (or "time sharing" as it was called) predates UNIX by almost a decade ... 🤔
@mikechappell4156