Which developments of the nineteen twenties contributed to an improvement in the American Standard of living. select 4 options.

The developments were the states, which grew over time creating better living for all US citizens.

Japan became even more isolationist than it had been.

Explanation:

Japan's isolation policy was completely executed by Tokugawa Iemitsu, the grandson of Ieyasu and shogun from 1623 to 1641. He published orders that really closed Japan to all immigrants and limited the Japanese from moving.