How did the crusades contribute to trade and learning

The contribution of the Crusades was that trade increased as Europeans traveled and became more familiar with exotic goods. Increased contact and trade was part of the reason for the rise of towns and cities in western Europe, starting in Italy. There teachings of Christianism and war tactics contribute to the crusaders.

d. japan's attack on pearl harbor

cultural/diplomatic relations. most medieval japanese   culture has chinese origins. writing, architecture etc.