Multiple choice One reason the Depression of 1929 was so severe in the United States was US industry had failed to modernize and expand following WWI FDR said the government shouldn't interfere in the economy. American economy was based on industry, & people lost jobs Depression did not impact Europe Reveal answer Fill a bubble to check yourself C Correct answer Explanation The US economy in 1929 was heavily industrialized. When the stock market crashed and demand plummeted, factories closed and mass unemployment followed, which exacerbated the economic downturn.