Answer:
First of all we have to define what a nation-state is and it is pretty much a Multinational State which is a country that contains more than one ethnicity with traditions of self-determination .
Because no state has a population that is 100% of a single ethnicity, every state in the world is to a varying degree multiethnic .
There is no such things as a PERFECT nation-state because the territory occupied by a particular ETHNICITY never corresponds precisely to the BOUNDARIES of countries .
In some multiethnic states, ETHNICITIES all contribute CULTURAL features to the formation of a single NATIONALITY .