Answer:A
the Incan civilization was known for the impressive waterworks in their city centers. Some of these included canals, fountains, drainage systems, and expansive irrigation.
One example of their advancement in this area is the Incan citadel called Machu Picchu which is said to be "the pinnacle of the architectural and engineering works of the Inca civilization" when talking about its water supply system.
D: the formation of the North Atlantic Treaty Organization (NATO)
Answer:
Countries with free-market economic systems influenced the revolutions that swept Europe in the late 1980s and early 1990s acting as "mirrors" or "models" upon which the revolutionary nations looked at themselves, seeking to compare their economies and quality of life. In other words, the free nations were the models that the citizens of the nations in revolution had: these revolutionaries sought to emulate the economic growth and political and social stability of these nations.