It looks like the cartoon is sort of mocking the Nazis. Or comparing it to America. You can tell my the symbol of the dude on the right’s shirt..
Well, it is like the Biblical story about the Tower of Babylon - in the beginning, there was only one language and all the people in the world spoke it. However, because of many disputes and quarrels, they all separated and created numerous new languages. The same thing happened in the real world (if you don't believe in what the Bible says) - there used to be Proto-Indo-European language, but over time, it developed many new languages as people grew apart and created new nations.
Answer:
1. War and insecurity 2. Economic crisis (poverty) 3. Overpopulation
Explanation:
1. War and insecurity - as example Syrian crisis and war against ISIS
2. Economic crisis (poverty) - mass immigration from Poland to USA in the late XIX and early XX century.
3. Overpopulation - mass immigration to Europe from African countries in the last few decades.
B. Free African Americans
Underground Railroad is a passage African Americans used to escape slavery.