The spread of Humankind to inhabit all the part of the Globe was a significant advancement in the Paleolithic age.
The Paleolithic Age is commonly known as the Stone Age, begun roughly 500,000 years ago and ended around 6000 B.C.E. People in this period produced complex tools and objects made out of stones. This age comprises the initial widespread use of technology as humans advanced from simplistic to a more complicated developmental stage and the spread of Humanity from the Savannas of East Africa to the rest of the world.
I believe the answer is Barbed Wire.
Befor the inventions of barbed wire, the Cattles are let to roam freely across the plains and the owners are required to pay a lot of cowboys to supervise them so they didn't go missing. Witht he invention of barbed wire, they can keep the cattle in a secure place without supervision.
The answer is D. "urged immedite emancipation of slaves in the unted states.
Arabia is the corresct answer