Why do historians believe happened to the teotihuacans and zapotec people?

How might the first nations have reacted when they saw that the europeans were moving onto their lands and disrupting their way of life? (this was when the europeans came to canada and tried to claim land to themselves)

Which of the following is a claim about ancient rome that a historian could build san argument around

In 1819, what did the united states obtain from spain for $5 million?