answer:Just one of the many effects on European society from the crusades was the introduction of arabic numerals to European society. Arabic numerals are the numbers we recognize today 1,2,3...etc. This was a major change from Roman numerals, and was much more effective.
Some basic effects of Europeans coming to North America are that the Native Americans caught new diseases which included smallpox, influenza, measles, and chicken pox. Explorers used superior fire power, like single shot muskets, to conquer natives.
