What is columbus impression of the new world

What would lead a historian to consider two events to have a relationship of correlation rather than causation?

The national women's suffrage association was formed in 1869 to obtain rights for women.

Which of the following led to a continuation of the treatment in the excerpt above? a)the brutality of the trans-atlantic african slave trade. b)spanish repression after violent native uprisings in new spain during the 16th century. c)european competition to quickly establish colonial holdings in the new world. d)the reliance of the spanish on native americans to provide labor under the encomienda system.