Answer:
Nationalism as the uniting force.
Explanation:
The Nineteenth century Europe witnessed the growth of a powerful nation state when German speaking states agreed to unite under the aegis of Prussia to form a greater nation called Germany. These states shared common language and nationalist feelings against bigger neighbouring empires like Britain and France.
The need to unite into a greater empire also became inevitable when Austrian influence started to threaten the disintegrated German speaking states. As a result, under the leader of Otto von Bismarck, these states came together as one nation and defeated Austria successfully.
At the same time, political leaders and activists used the feelings of nationalism as the main strategy to unite German speaking states into one nation. Therefore, the image depicts the factor of "nationalism" as uniting force of Germany.
