Which is the oldest civilization based on reliably dated evidence?
   Alyosha, 14, Bombay, India

Dr. dig responds:
This depends so much on how we define a civilization! The first permanent farming settlements were established in the Middle East in approximately 8000 B.C. By 6000 to 5500 B.C., irrigation has developed and the roots of the Mesopotamian civilization were in place. By 3300 the city of Uruk had two great temples, and its priests and accountants had developed cuneiform writing. Other early farming communities are India (7000 B.C.) and China (6500 B.C.), both of which led eventually to civilizations. The Indus state emerged in 2700 B.C., while the Xia dynasty in China developed in 2100 B.C.