How did john d. rockefeller horizontally integrate his monopoly in 1880?

a. he purchased iron mines around the country to add to his business.
b. he created a trust that controlled ninety percent of the nation's oil refineries.
c. he created a trust that controlled oil wells, refineries, and distribution networks.
d. he purchased coal plants around the country to add to his business.

What is the difference between an independent and a dependent variable?

Wiiy is limportant to consider the historical context surrounding an event when making a historical interpretation? o a. a conclusion that does not consider context is a generalization rather than an interpretation. b. historical interpretations are not valid if they are written in a similar context as the event. o c. every historical interpretation must consider the long-term consequences of an event. o d. the setting of an event can provide insight into why it happened.

The development of england as a nation-state occurred because of increasing?