प्राचीन बौद्ध ग्रंथों के अनुसार, छठी शताब्दी ईसा पूर्व के दौरान भारतीय उपमहाद्वीप में कितने 'महाजनपद' अस्तित्व में थे?

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?