Answer :
The factors that contributed to the decline of the Indus Valley civilization are options A, B and C:
- The surrounding land was severely deforested.
- Indus Valley populations migrated to Central Asia and Africa.
- Diseases reduced the population.
Why did the civilization of the Indus Valley collapse?
The Indus River Valley's civilization started to deteriorate from 2500 BCE as people moved eastward to the Himalayan foothills. Here, their civilisation changed from one dominated by great cities to one dominated by tiny farming communities. Most Harappan cities had been virtually abandoned by 1800 BCE.
Therefore, Because they believed that the climate was changing, the Indus Valley Civilization declined. Additionally, there were nomads from central Asia (the Aryans), who altered the cultural landscape.
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