Respuesta :
Answer:
River Indus.
Explanation:
- The alternation of floods and droughts in the Indus Valley forced people to work together to build systems of dams and canals for flood defense and irrigation.
- Thus, around 2500 BC Christ in the Indus Valley formed the cities of Harappa and Mohenjo Daro.
- They were founded by the Dravids, the oldest population of India.