Why were the indus river and ganges so important to ancient india

The Indus River created the Indus Valley Civilization where new techniques were developed in handicrafts and metallurgy. They are also famous for their urban planning, baked brick houses, elaborate drainage systems, water supply systems and clusters of large non-residential systems which were all made possible by the river which gave them irrigation systems, food, water and helped them grow plants. For the Ganges River, civilization was present by the Ganges Basin and many powerful empires sprouted around the river for the same reasons as the Indus River.

The answer to this question is  c. pharmaceutical accumulation  reclaimed water refers to the water that being used again after it already  used for agricultural purposes.this type of water often contains pharmaceutical accumulation because of the chemical fertilizer that is used for the plants is absorbed into the water.