“Some of the earliest civilizations flourished and cities established on the plains of the rivers Indus valley” give reasons.

Explanation:

Mesopotamia was one of the earliest river valley civilization, starting to form around 4000 BCE. The civilization was created after regular trading started relationships between multiple cities and states around the Tigris and Euphrates Rivers. Mesopotamian cities became self-run civil governments.

answer; ///(c) i believe that the correct answer is ethnic relations bear many similarities across different global; good luck

answer; randomization;