<span>D. It was an ecological transformation.</span>
Columbian Exchange was the introduction of Old World plants and animals into the New World and the other way. An example of this was the introduction of tomatoes and potatoes to Europe.
The secret police attempted to identify citizens who opposed the Communist Party and who could undermine it.
They gave soldiers better advantage at defeating the enemy and defending the country.
Examples Include:
Tanks
Guns
Technological advances such as Airplanes
It is not an exaggeration to say that the US underwent a "transportation revolution" during this time. Before paved roads occurred, it cost practically the same amount to ship something to Europe as it did to send it on land in the US. Paved roads of course increased economic output but making the transfer of supplies much easier.
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