Answer:
C. Change "have been" to "were"
The Santa Fe Trail was America’s first commercial highway. Traders established the trail—which connected Missouri to Santa Fe, New Mexico and covered some 900 miles of the Great Plains—in 1821. Before its demise due to the completion of the Santa Fe railroad, the Santa Fe Trail served as a thoroughfare for countless traders, pioneers and America’s military, and it played a crucial role in America’s westward expansion.
Well for starters once these civilizations started to get an adequate food supply they started to do other things and started to farm which let people settle do and build cities
It increased the purchasing power of rich Americans.
Brehnev welcomed Nixon to visit Moscow. The Soviet Union reacted to the standardization of relations amongst China and the United States by having Brehnev welcome Nixon to Moscow. President Nixon trusted that normalizing relations with china drive a wedge amongst China and the Soviet Union.
