You have learned about the rise and fall of the soviet union and its influence in europe. who or what was responsible for the end of communism in europe?

I think that Mikhail Gorbachev was responsible for the end of communism in Europe. By allowing local officials to have more power, he gave up some of his own power, potentially to those who may disagree with communism. While a good decision from him, it was not in communism's best interest. This gave these countries an urge to see where the boundaries are. Countries such as Hungary elected their own presidents and surprisingly, the USSR let them do this.

the principle of popular sovereignty is most closely related to the concept of

democracy