The answer is a patent and is valid for 20 years
The attacks on the twin towers and pentagon in 2001
The Columbian Exchange has brought new species to Europe. This includes new plant species, such as tomatoes and potatoes which have help combat hunger in Europe. This can be seen for example through the fact that when potato has a blight it caused the great famine in Ireland. However, the Columbian Exchange was not only positive for Europe as it also introduced sicknesses such as syphilis.
The Sibley Commission recommended that local school systems be allowed to decide if they would act by a probable court order to integrate public schools or if they would close them. When Governor Vandiver ordered to close UGA because of forced integration, people changed their minds about closing down public schools.