The twentirs was a time ofbecause Americans enjoyed

i think the answer is c, rivers.

explanation:

sometimes, borders fall along natural boundaries like rivers or mountain ranges. for example, the boundary between france and spain follows the crest of the pyrenees mountains. for part of its length, the boundary between the united states and mexico follows a river called the rio grande. the borders of four countries divide africa’s lake chad: niger, chad, cameroon, and nigeria.

after world war ii, the united states and the soviet union were the major economic, military, and political powers. the world was bilateral multipolar bipolar unilateral

after world war ii, the united states and the soviet union were the major economic, military, and political powers. the world was bipolar.  

the great leap forward, mao zedong's plan to increase china's agricultural and industrial production, was an overwhelming success. true false

the great leap forward, mao zedong's plan to increase china's agricultural and industrial production, was an overwhelming success. true.

explanation:

four sitting presidents have been assassinated while in office but the first was abraham lincoln,

democracy

explanation: