What factors have led to American involvement in world conflicts?(For Cold War)

the emergence of nuclear weapons, and the fear of communism in the United States

Explanation:Historians have identified several causes that led to the outbreak of the Cold War, including: tensions between the two nations at the end of World War II, the ideological conflict between both the United States and the Soviet Union, the emergence of nuclear weapons, and the fear of communism in the United States.

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.