What was the united states' major concern about their former ally, the soviet union

Answer :

The Bolshevik revolution in Russia was the cause of fears in US and led to Red Scare. Red scare was defensive societal response to the spread of communism in US. The Red scare lasted till mid 1920's and led to the suspension of civil liberties as the people were suspected of having ties with the communists. The red scare caused chaos in the United States. It was initiated by senator Joseph McCarthy, who claimed that there were communist working in US to subvert the US constitution from within. Due to this the suspected communists were exposed and purged, blacklisted and their civil liberties were restricted. in US. Hence we can say that the spread of Communism in US was one of the major concerns  of US.

answer; ///i believe that the correct answer is (a) the great depression

the answer to your question is a. the salt plains

in 1811, he led an expedition, known as the george c. sibley expedition, to improve relations with the pawnee and kansa tribes, and also to locate the rumored jefferson's salt mountain