Explanation:
The Chalcolithic period, or Copper Age, was an era of transition between the stone tool-using farmers of the Neolithic and the metal-obsessed civilizations of the Bronze Age. The Copper Age was really a phenomenon of the eastern Mediterranean regions, and occurred from roughly 3500 to 2300 BCE.
Import
The us brings in goods from an outside source
C. They made it easier to perform calculations.
B overstepping its authority