Question

How did German industry help create political unity?

Railroads linked factories.

The failing economy helped create political unity.

Both are correct.

Answer 1

In the 19th century, Germany began a stage of rapid economic growth and modernization, led by heavy industry. By 1900 it had the largest economy in Europe, a factor that played a major role in its entry into World War I and World War II. The large economy allowed for political unity. The people were more inclined to keep those they felt help them be prosperous in power.
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