Ios is unix c gui?

Question

iOS

My friend and I are arguing that: ios is unix with gui (his thought) and ios is a completely different system (my thought). I want to know: which one of us is right? (preferably with explanation)

Answer 1

https://ru.wikipedia.org/wiki/IOS
https://ru.wikipedia.org/wiki/XNU
No thanks.

Answer 2

ios is a microkernel with userland from freebsd and a bunch of their developments for the GUI
In general, it's not productive to argue. Even Windows comes from these ideas, but the devil is in the details

Answer 3

ios is freebsd with gui. Your friend is right.