They formed in river valleys, that is where all of the first one's formed.
I think you forgot to give the options along with this question. Based on my knowledge and assumption, i am answering the question. Creating a common, multicultural society is an important goal of European unification. I hope that the answer has come to your help.
Hegira refers to the prophet's move from Mecca to Madina
Not 100% sure and I'm sorry about that but I would say religion. I hope I helped.:)