American or Italian?

Naturally when we think of Italians, we picture the pasta, cheese, cannoli, and wine that the Italian culture practically praises. I have never been to Europe, but I've talked to a handful of people who have been to Italy, especially Rome.

Each of them said that Italians can easily pick out who is American and who is not.
How can they tell? 
Can Americans pick out Italians in the United States?
Do these women look Italian or American?

1. Alyssa Milano
Many remember her from the TV show, Charmed. She married David Bugliari in 2009 in New Jersey. Italian or American? 

2. Elisabetta Canalis
Many remember her as George Clooney's flavor of the month. She is also known for competing on Dancing with the Stars. Italian or American?

3. Margaret Mazzantini
Born in Ireland, this lovely red head is a famous writer and novelist. But is she American or Italian?

4. Paola Cortellesi
This lovely lady has starred in about 20 movies. She is an actress, voice actress, and singer. Does she look American or Italian?