An archaeologist was able to determine the sites by the bricks similar but was old found in the area where they lay railroads.
Step-by-step explanation:
- While railroads were constructed in Pakistan the engineers were searching for ballast which is used for railroad construction to drain water from the railways.
- Archaeologists later discovered the settlements along the Indus river, thousands of clay pellets with writings older than Sumerian, combs, pottery, seals, urban, plans with grid pattern during the excavation process.
- Both Harappa and Mohenjo Daro is a part of Indus Valley Civilization. The period of the excavated materials and artifacts is determined by the process name called Radio-Carbon Dating in which the age of the carbon can be accessed.