Answer:
[tex]{\fcolorbox{black}{skyblue}{\red{answer}}}[/tex]
By 1800 BCE, the Indus Valley climate grew cooler and drier, and a tectonic event may have diverted or disrupted river systems, which were the lifelines of the Indus Valley Civilization. The Harappans may have migrated toward the Ganges basin in the east, where they could have established villages and isolated farms.
