问题是什么?英文回答这个问题 不是翻译一下 谢谢The magnetic compasspromotesthe opening of Rota Nova.and providesnecessary condition for the Discovery of America .It also promotes the business trade in the world.The gunpowder changes the way of war and helps the European asset class to destroyfeudalism.Boosting the development of European history.The invention of silk helps to open the business trade way with Europe