Trees using magnetic potential energy to help them move along the track. which statement below shows how they do this? A. The magnets in the tree and the track repel.
B. The magnets in front of a train pull the train forward.
C. The magnets behind the train push the train forward.
D. All of the above.

relations between the soviet union and the united states were driven by a complex interplay of ideological, political, and economic factors, which led to shifts between cautious cooperation and often bitter superpower rivalry over the years. the distinct differences in the political systems of the two countries often prevented them from reaching a mutual understanding on key policy issues and even, as in the case of the cuban missile crisis, brought them to the brink of war.

the united states government was initially hostile to the soviet leaders for taking russia out of world war i and was opposed to a state ideologically based on communism. although the united states embarked on a famine relief program in the soviet union in the early 1920s and american businessmen established commercial ties there during the period of the new economic policy (1921–29), the two countries did not establish diplomatic relations until 1933. by that time, the totalitarian nature of joseph stalin's regime presented an insurmountable obstacle to friendly relations with the west. although world war ii brought the two countries into alliance, based on the common aim of defeating nazi germany, the soviet union's aggressive, antidemocratic policy toward eastern europe had created tensions even before the war ended.

federal power is further limited with a system of checks and balances that gives each branch of government a measure of power over the others.

explanation:

2. a land bridge connected asia and north america thousands of years ago.

4. crossing the land bridge would have been simple for the first migrants.

5. people might have crossed a land bridge while hunting animals.