Final answer:
President Kennedy responded to the Soviet Union's placement of nuclear missiles in Cuba by implementing a naval blockade, known as the Cuban Missile Crisis.
Step-by-step explanation:
President Kennedy responded to the information that the Soviet Union was placing nuclear missiles in Cuba by implementing a naval blockade. This blockade, known as the Cuban Missile Crisis, aimed to prevent further Soviet shipments of military weapons to Cuba. It was a diplomatic and military confrontation that brought the United States and the Soviet Union to the brink of nuclear war.
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