Answer:
Population growth and diversity.
Explanation:
In an area with multiple enthic groups and people, socilization and growth leads to others exploring new cultures and learning about them and sharing them. This could also lead to new cultures being forged from two original cultures.
The growth of the empire continued to increase their confidence.
The Truman Doctrine basically said that America would provide help even military help to any country that was under threat of being taken over by communism. By contrast, the Marshall Plan provided aid in the form of food and money to countries in Western Europe whether they were being threatened by communism or not.
