They created the number system and discovered that the earth was round by studying eclipses.
Hope this helps.
Answer:
"Pre-Columbian civilizations, the aboriginal American Indian cultures that evolved in Mesoamerica (part of Mexico and Central America) and the Andean region (western South America) prior to Spanish exploration and conquest in the 16th century. The pre-Columbian civilizations were extraordinary developments in human society and culture, ranking with the early civilizations of Egypt, Mesopotamia."
Explanation:
The radical republicans with open arms invited Johnson but after they realized he was gonna follow in lincolns footsteps they turned on him. They mad it as hard as it could be to pass anything and they were going to have him impeached but he didn't get impeached because of one vote
