How do you tell the difference between a Turkish and an Italian/Greek person?

I'm not sure why it matters, but usually it's in the facial features. Not everyone looks like their nationality. Italians have certain features that are unique to Italians. Same as Greeks. The Turks as a tribe are actually of Western Chinese origin, so they are very mixed, ranging from Russian looking, to very middle eastern. But the same can be said of any country in that area. It's the foundation of modern civilization.