Hello There! ^_^
Your question: What were the three main Indian groups before European explorers arrived..?
Your answer: The Mayan, the Aztecs and the Incas were the three main Indian groups before European explorers arrived.
Hope this helps!
The Atlantic Ocean lies between North America South America Europe and Africa
September 5, 1793 - July 27, 1794
Rome was one of the richest and protected cities, and I can see there two correct options. I bet one than more is acceptable, so B.
Rome was built on seven hills, which offered natural protection from invaders. and D.
The climate of Rome was good for growing a variety of crops. are the truthful reasons why this city has a good site.