Questions: The economic boom of the 1920s was primarily caused by the new economic policies of the League of Nations. development of new consumer goods industries. advent of advertising on radio. elimination of barriers to international trade.

The answer is the development of new consumer goods industries.

The League of Nations, established after World War I, primarily focused on maintaining peace and preventing future conflicts. It did not play a significant role in shaping economic policies that led to the economic boom of the 1920s.

The 1920s, often referred to as the "Roaring Twenties," saw significant economic growth driven by the development of new consumer goods industries. Innovations in manufacturing, such as the assembly line introduced by Henry Ford, led to mass production of automobiles, household appliances, and other consumer goods. This increased production made goods more affordable and accessible to a broader segment of the population, fueling consumer spending and economic growth.

While the advent of radio advertising did contribute to the economic boom by promoting consumer goods and encouraging spending, it was not the primary cause. The development of new consumer goods industries had a more substantial impact on the economy.

Although international trade played a role in the economic landscape of the 1920s, the elimination of trade barriers was not a primary factor in the economic boom. The domestic growth of consumer goods industries had a more direct and significant impact on the economy during this period.