The technologies were only used to observe enemies but as their effectiveness became apparent, both sides started to dismantle what they were using. For example, they shot down the planes that they would see causing more death.
The statement that provides the most accurate description of the Columbia Exchange is E. African population to the Western Hemisphere; Western Hemisphere food to Europe and Africa; African and European diseases to the Western Hemisphere. The Western Hemisphere had very arable land and thus was a great source of food and agricultural materials for the more populated Europe and Africa. European settlers used slave labor in the Western Hemisphere to harvest that food, labor that came in the form of African peoples. However, the indigenous peoples in the Western Hemisphere were not accustomed to the diseases of Africa and Europe.
I believe the first answer is The Turks captured Constantinople closing the path to the Silk Road. The second is Europeans developed the economic system of mercantilism and needed reserves of gold and silver. Hope I helped!
