10. how did social studies cross over into science? hint what
was invented over 3000 years ago that societies needed for
their daily trading of goods? ( explain)

Barter system was invented over 3000 years ago which society needed for their goods trading through which social studies crossed the science.

Barter system existed centuries ago when coins were yet to be invented.  People did not have any currency back then. To make trading a successful practice, goods were exchanged for goods. That is, a person exchanging earthen pots for rice or wheat. The system worked for several centuries and had flaws of its own.

For instance, the trade itself wasn't always fair. The guarantee of the goods was not ensured. Nor was the reliability of the seller. Other than that, people had to find the sellers who would want to exchange with their goods. Despite everything, the barter system continued until coins were invented.