What was the backbone of the american en the 1920?

Which of the following inventions most directly allowed ancient farmers to produce a surplus ?

What are the biggest challenges facing the average american citizen today? explain.

Hich explains why the constitution gave congress the power to create a system of federal courts? the constitution wanted congress to share power with the judicial branch. the constitution anticipated the need for courts lower than the supreme court. the constitution wanted congress to share power with the appellate courts. the constitution anticipated the need for courts equal to the supreme court.