The use of rifles and other military technology was unmatched by locals.
Explanation:
The Europeans had many advantages because of the industrialization when compared to the areas they conquered. And while all of those things played some role, the most important was the military advantage, as the area needs to be conquered and controlled.
The advancements in the military technology, such as the riffles and the gunpowder cannons, gave huge advantage over the locals. The weapons of the Europeans were more efficient, able to cause more casualties, and from greater distance thus often avoiding chest to chest combat.
