What natural boundary helps form the border between the United States and Mexico? hopes this helps

The natural boundary that extends along a large portion of the United States border with Mexico is the Rio Grande. This separates Mexico and Texas.  Elsewhere to the west, there is no natural boundary except the Colorado River for a relatively short stretch.

Explanation:

The Rio Grande runs along 1,254 miles of the border between Texas and Mexico,  but west of the city of El Paso there is no natural geographic barrier except for a small stretch of the Colorado River in Arizona and California. The Colorado River forms the border with Mexico for a relatively short distance of 17 miles, between Baja California and Arizona.  The river runs along the border between Mexico and Arizona until it reaches Luis Rio Colorado where the river crosses into Mexico entirely. The dams and diversions the United States has built have made this part of Mexico much arider than it was in the past. There were marshlands in the river delta before the United States started diverting water at various points into California and Arizona to favor agricultural development.

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.