Final answer:
The subject is History. Black Tuesday refers to the stock market crash of 1929 that led to the Great Depression.
Step-by-step explanation:
The subject of this question is History. The day that the bottom fell out of the market and became known as Black Tuesday refers to the stock market crash that occurred on October 29, 1929, which marked the start of the Great Depression in the United States. This event had a significant impact on the economy and the lives of millions of people.
Learn more about Black Tuesday and its significance in history