The cold war was caused by fear, not aggression. to what extent does this view explain how the cold war developed between 1945 and 1949?

Well, fear is created when there is a threat. WW2 Had just ended, so of course America did not want any other nation to become more powerful than them, for the idea that it would end up being like Germany. Americans also wanted to protect democracy, so communism was a major threat to the USA and it's beliefs. Naturally, America wanted to prove dominance to the USSR, thus the beginning of the cold war.