-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 above suggest about the Cold War Era?
a.
Throughout the period, the US and the USSR were reluctant to solve conflicts.
b.
The level of tension between the US and the USSR varied.
c.
Economics played a key role in causing conflict between the US and the USSR.
d.
The UN was instrumental in reducing tensions between the US and the USSR.