Which statement is not true?
states now forbid operators of theaters, hotels, and restaurants to refuse service to minority groups.
beginning about 1890, approximately twenty states enacted segregation laws directed primarily at african americans.
slavery was an established institution until the twelfth amendment was ratified on december 18, 1865.

Beginning about 1890, approximately twenty states enacted segregation laws directed primarily at African Americans.
- this is a true statement.

This segregation also included Asians and Mexicans.

how about this statement:

Slavery was an established institution until the Twelfth Amendment was ratified on December 18, 1865. ???

It's false because it was the Thirteenth Amendment, not the Twelfth. The Twelfth Amendment was ratified in 1804 and it concerned the election of the President and Vice-President