The doctrine that explains the physical world as being composed of ultimate, indivisible particles (atoms) which combine to form all material substances is a key feature of which one of the following philosophical schools?

Gautama Buddha was born at ______.

Consider the following statements regarding a historical period: (i) Animals began to be used for transporting goods during this period. (ii) Trade and transportation developed significantly in this era. (iii) Pottery making using the potter's wheel started in this age. Which historical period is described by the above statements?