Final answer:
Germany showed the divisive effects of the Cold War most clearly.
Step-by-step explanation:
The pre-WWII country that showed the divisive effects of the Cold War most clearly was Germany. After World War II, Germany was split into two separate countries - West Germany, supported by the United States and Western allies, and East Germany, supported by the Soviet Union. This division highlighted the ideological and political differences between the two superpowers and demonstrated the intensity of the Cold War.
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