The correct answer to this open question is the following.
The emergence of advanced civilizations in Meso and South America came way after the emergence of the four early river valley civilizations.
The first civilization, and the oldest one on planet Earth, was Sumeria. Sumerians settled in the middle of the Rivers Tigris and Euphrates, in modern-day Iraq.
According to historians, Sumerians developed modern agriculture techniques to grow good crops.
Unpredictable flooding of the rivers in Mesopotamia affected their crops until they learned to take advantage of this situation to grow crops in that fertile soil.
Due to this knowledge. Sumerians could establish powerful city-states such as Nippur, Eridu Lagash, Kish, Ur, and Uruk.
Something similar happened with ancient Egypt. They settled next to the banks of the Nile River. Agriculture techniques helped them to create one of the greatest empires of ancient history.
The same with the Harappa civilization or the Indus Valley civilization in modern-day India. They settled next to the Indus River. The same case for ancient China. They settled next to the Yellow River.
Mesoamerican and South American civilizations came many years after those ancient ones.
Historians and archeologists agreed that the Toltecs were the first civilization in Mesoamerica, followed by the Toltecs, the Zapotecs, the Teotihuacan, the Mayas, and the great Aztecas who founded the impressive city of Tenochtitlan, modern-day downtown Mexico City.
The Inca was the most important empire in South America. They owned and ruled most of the Andes region. For these civilizations, agriculture was of the utmost importance to survive and thrive.
In the case of the calendars, the Sumerians had an impressive knowledge about astronomy and the importance of time. Mesopotamia was a place of priests who were in constant contact with the gods to deliver these teachings and predict eclipses and weather changes.
The Mayans also had great knowledge of astronomy. They built an observatory in Chichen Itza, the archeological zone in the Yucatan Peninsula, in México. They created the Tzolkin, the calendar of 365-days. They also created the Haab calendar and the Long Count Calendar.
