The correct answer is true.
It is true that by 1807, approximately 500,000 Africans had been brought to the United States unwillingly and forced into slavery.
That statement is correct. That is why the United States Congress decided to prohibit the African slave trade on March 2, 1807. From then on, the government expressly prohibited the importation of African people to be used as slaves in the United States. That same year, Great Britain also prohibited the African slave trade, however, the slave trade to Brazil and South America continued until the 1860s.
