Answer:
a. Czechoslovakia
Explanation:
<em>"On August 20, 1968, the Soviet Union led Warsaw Pact troops in an invasion of Czechoslovakia to crack down on reformist trends in Prague. Although the Soviet Union's action successfully halted the pace of reform in Czechoslovakia, it had unintended consequences for the unity of the communist bloc."</em>
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more detailed info found here; <em>https://history.state.gov/milestones/1961-1968/soviet-invasion-czechoslavkia</em>
The first astronomer to state the fundamental laws of planetary motion, Kelper was also known for his works in geometry, optics and philosophy.
Answer:
spirit of cooperation ended abruptly in 1960, when the Soviets shot down an American U-2 spy plane over their territory"-755
Explanation:
President Dwight D. Eisenhower (1890-1969) was the 34th president of the United States of America between 1953 to 1961. He worked well with the Soviet leader Nikita Khrushchev to thaw the cold war at the end of 1950s. In May 1960, their cooperation ended prematurely when diplomatic crises erupted because the Union of Soviet Socialist Republics (USSR) were said to have gunned down an American U-2 spy plane in Soviet air space.
President Eisenhower was compelled to admit to the soviets that the central intelligence unit of his country has been sending out spy missions for several years in the USSR.
