Question

1. why was black thursday so devastating?

no one on wall street understood that the market was crashing, so they just continued to sell.
it forced companies to reveal their real values, as opposed to their paper values.
manufacturing companies were forced to stop issuing stock, so they lost value.
the stock market lost nearly one quarter of its entire value on that one day.

Explanation:

Black Thursday (October 24, 1929) was the start of the 1929 stock market crash. Its devastating impact stemmed from the massive, sudden loss of market value in a single day, which triggered panic selling and the broader collapse of the market and economy. The other options are incorrect: Wall Street participants did recognize the crash and panicked, the crash did not force companies to reveal real values, and manufacturing halting stock issuance was not the core cause.

Answer:

The stock market lost nearly one quarter of its entire value on that one day.