Answer:
Christopher Columbus introduced horses, sugar plants, and disease to the New World, while facilitating the introduction of New World commodities like sugar, tobacco, chocolate, and potatoes to the Old World.
Explanation:
Cause It will understand it to you.
Http://m.historyextra.com/feature/complex-crimea-history-relationship-Russia-Ukraine-Crimea
Explanation:
Contamination can have undesirable consequences in real experiments, some of them are related to the feelings that may arise in the research participants, the contamination bias reduces the differences between the research groups, and can cause a comparison between the treatments of each different group, the which can generate conflicts and rivalries on the part of groups that consider themselves to be inferior to others. These contamination-related problems can significantly interfere with the research results.
