C because the US wanted to own everything (I passed advanced US History with straight A's bruh)
For something to be prehistoric it has to be before the times that record history. The Sumerians had written laws so they are not prehistoric because they record history.
<span>an intense military campaign intended to bring about a swift victory</span>
Technological innovations during this time in the United States primarily had negative impacts on factory workers since they introduced very dangerous working conditions, and positive impacts on middle-class urban residents since their income increased (in general).