<span>I think nationalism because people were concerned with their importance in the world. They wanted to feel their land and culture were better and more sophisticated than others so they would seek out other areas to validate their feelings.</span>
It is between 1 and 3. I think it is 3: a common language. Many different. ultures have different languages. Food, clothing, and shelter can differ but I believe that a language bonds a culture together. The way they live.