What building projects did the Inca carry out?

The Incas were certainly skilled stonemasons. They used granite or limestone to build their cities, these materials were available locally. To cut the rocks they used stones, metal tools made of bronze or copper, pieces of wood and water.

Explanation:

The Incas build the famous Machu Picchu. They also built a system of roads.

answer; i believe the correct answer is (4) flip a coin as each participant arrives,heads indicates assignment to the first group: tails indicates assignment to the second group;