How did the culture and values shared by greeks both united and divded them?

It divided them because the Greek city states were all proud of their own culture, traditions and heritage. This led to many internal conflicts and struggles. At the same time, however, in times of need when there was a strong outside force (Persian empire for example), they joined together as their culture and values bonded them together to fight a common enemy.

The american civil war

The answer is d. spain.