-Berlin Blockade (1948-1949) -Premier Khrushchev’s visit to the United States (1959)
-Cuban missile crisis (1962)
-Nuclear Test Ban Treaty (1963)
-Joint Apollo-Soyuz space mission (1975)
-Russian invasion of Afghanistan (1979)

What does this list of events suggest about the Cold War Era?
a.
Throughout the period, the United States and the Soviet Union were reluctant to solve conflicts.
b.
The level of tension between the United States and the Soviet Union varied.
c.
Economics played a key role in causing conflict between the United States and the Soviet Union.
d.
The United Nations was instrumental in reducing tensions between the United States and the Soviet Union.