Which three factors were part of european imperialism?

Three factors that spurred American imperialism were the need to expand even after the frontier had vanished, with industrialization warranting further claim to more resources, the growing importance of foreign trade to the American economy and the desire to compete with European empires for power. Because of this mixture of cultural, economic and political factors, the U.S. was influenced to practice imperialism, particularly during the late 19th and early 20th centuries.