Question

What action did the Soviet Union undertake after the formation of the North Atlantic Treaty Organization?

They were the first to join

Formed the Warsaw Pact

Invaded Afghanistan

Built the Berlin Wall

Answer 1

The Warsaw Pact

Step-by-step explanation:

The Warsaw Pact was created in reaction to the integration of West Germany into NATO in 1955 per the London and Paris Conferences of 1954, but it is also considered to have been motivated by Soviet desires to maintain control over military forces in Central and Eastern Europe.