Final answer:
The two main factors that contributed to America becoming an economic power are its abundance of natural resources and its large unified market.
Step-by-step explanation:
There are several factors that contributed to America becoming an economic power. One of the main factors is the abundance of natural resources. America had vast areas of highly productive farmland, and it also had abundant reserves of timber, coal, iron, and oil. These resources helped fuel industrialization and economic growth.
Another factor is the United States' large unified market. The country has a population of over 300 million people, providing a large consumer base for businesses to sell their products and services to.