What object was used to balance early scales?
The earliest surviving weighing scales date back to around 2000 B.C. from the Indus Valley Civilization. From these artifacts, scientists deduced that the scales worked by an intricate balancing act — stones were placed on the plates on one side, and whatever was being weighed or evaluated on the other until equilibrium was reached. Polished stones for this very purpose have been discovered in the same ancient settlements as the scales.
Answer: The correct answer is Polished stones.