Answer:
1. The Mayans discovered the number zero which they used to measure time. Also the Babylonians and Hindus independently discovered the number zero. The Mayans used only three symbols to represent numbers: the point, whose value is 1; the line, whose value is 5; and the snail / shell whose value is zero.
2. The Aztecs created a calendar system. The first calendar consists of 365 days. This was the agricultural calendar they used to plan their crops and harvest. The second calendar was a sacred calendar consisting of 260 days. This calendar was used to make predictions.
3. The Shuar tribe is the only group in the world that created shrunken heads. The Shuar lived in the Amazon between Ecuador and Peru. Shrunken heads were the heads of the enemies who won their battles. They managed to reduce heads using their extensive knowledge of anatomy and chemistry. They believed that the spirit of their enemies was trapped in the shrunken heads and used them as a talisman. The Shuar tribe still exists today but in the 1950s they were prohibited from continuing their practice of creating shrunken heads.
4. Many of these civilizations built architectural wonders that scientists have not yet been able to explain how they were built. Among these wonderful structures are Machu Picchu in Peru, the city of Tikal in Guatemala, and the city of Teotihuacán in Mexico. The level of knowledge of engineering and architecture that these civilizations possessed was evidently very advanced.
5. They had extensive knowledge of healing plants and in certain cases they also practiced surgery as is the case of the Incas who practiced brain operations.
Step-by-step explanation: