Which two natural resources were the most necesarry for the development of American industry during the 19th cenutry?

During the 19th century, coal and iron were the two Natural Resources most necessary for the development of American industry. Coal fueled steam engines and factories, driving the expansion of transportation networks and manufacturing. Iron was essential for building machinery, railroads, and infrastructure, laying the groundwork for industrial growth and urbanization. Together, these resources played a crucial role in powering the Industrial Revolution in the United States.