"<span>Introduction of American plants such as maize to Europe" is the only option that was a part of the Columbian exchange, since this exchange revolved primarily around the exchange of goods from the New World to Europe. </span><span />
World War 1 was not fought in Africa but African Americans were NOT allowed to fight with white people.
1. the steel strike of 1919
2. seattle general strike
3. the great strike of 1919
