Answer:
2) Refusing to join the League of Nations
Explanation:
The best action that demonstrated the United States' effort to isolate itself from European conflicts after World War I is "Refusing to join the League of Nations."
This is evident in the fact that the United States Congress failed to pass the bill to join the League of Nations. This is based on the idea or some Isolationists' fear that it might make the United States drawn into International issues unnecessarily.
•Industry vs. Farming. ...
•States' Rights. The idea of states' rights was not new to the Civil War. ...
•Expansion. As the United States continued to expand westward, each new state added to the country shifted the power between the North and the South. ...
•Slavery. ...
The correct answer for the question that is being presented above is this one: "becoming more self-sufficient." Trading centers in other countries helped the mother country in all of the following ways except for: becoming more self-sufficient gathering sufficient.
The last one invest in heavily in machines and factories as well as new business...(of topic but do you go to rhs)