Answer:
thank you pro hole for answering
The best way to check the reliability and validity of a resource is : B. analyze the author's education and professional background
What they did before and how china became a civilization
The ancient Romans used their engineering skills to build aqueducts, bridges, roads, domed structures, the hypocaust heating system and any other building projects they undertook.
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West Africa before Portuguese was very wealthy Kingdom because of the Natural sources and trade that was present at that time. It was a thriving Kingdom as the gained lot of money and wealth from the goods that were traded from the region.
Europe after crusades was introduced to goods from Asia and the Middle East hence its or a boom in trade after crusades. Europe especially during the Mongol period started involving more in trade with Asian goods for being useful and attractive.
America before Columbus was confined local trading rather than trading goods from far away. Be more engaged in Civilization surrounding it they were more of regional traders such that they could sustain a good life.