Answer: Democracy and capitalism.
Step-by-step explanation:
During the late 1800s and early 1900s, America was experiencing two revolutions: a political one, and an economic one. These processes were the basis for the development of democracy, and capitalism.
The second half of the 1800s showed America´s fastest growth, with important increases in production, salaries and general wealth. There was fast industrialization, population growth, and overall prosperity.
Between the 1890s and 1920, political reforms expanded democratic representation.