Final answer:
The prosperity of the 1920s was an illusion as indicated by the rampant consumer debt, a growing income gap, and overproduction in major industries.
Step-by-step explanation:
The evidence that showed the prosperity of the 1920s was an illusion includes the widespread increase of debt among individuals. People were buying consumer goods on credit, contributing to a false sense of economic stability. The income gap between workers and management increased, leading to an uneven distribution of wealth, and fewer Americans could afford to participate in the economy fully. Furthermore, overproduction in various industries coupled with not enough consumers able to purchase goods led to a fragile economic foundation with the stock market crash looming ahead.