The best option would be the <span>C) increased used of electrical appliances.
Hope this helps...
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Answer;
-West Africans were already to the Europeans diseases
Explanation;
They originally enslave American Indians, but three things put a stop to it. First, the Indians were all dying of epidemic diseases, which Africans had already been exposed to. Second, the Indians, being native, had a better knowledge of the land and its peoples, which made escape/revolt attempts more likely to be successful. Third, in response to debates about Spain and Portugal's treatment of indigenous people, the pope issued a bull in 1531 that banned the enslavement of American Indians.
As to why Africa, slavery had already existed in Africa for centuries. The Spanish and Portuguese had been exposed to it through their contact with the Moors of North Africa. So when they needed more labor in their American colonies, they simply bought slaves from one of the various kingdoms of West Africa and shipped them overseas.
"C. was overthrown by invading Mongol tribes in A.D. 1279" would be the best phrase describing China's Song Dynasty, but this was of course not always the case.
<span>as prices rise, so will supply, and as prices fall, so will supply. </span>
3. The literacy rate began to rise as interest in learning grew.
4. Books became available to many people throughout Europe.
Before the results of the printing press, when Johannes Gutenberg invented it in 1440, only about thirty percent of European adults were literate (could read and write). His invention flooded Europe with printed material which is when literacy rates began to rise after interest in learning increased.
