Which advancement most helped increase trade during the post classical era

The growth of inter-regional trade in luxury goods (silk and cotton textiles, porcelain, spices, precious metals and gems, slaves, exotic animals) was encouraged by significant innovations in previously existing transportation and commercial technologies--including caravanserai, compass use, the astrolabe, larger ship designs in sea travel--and new forms of credit and the development of money economies (Bills of exchange, Credit, Checks, Banking Houses, Use of Paper Money).

Advancement in technologies.Improved transportation technologies and commercial practices led to an increased volume of trade, and expanded the geographical range of existing and newly active trade networks

Explanation:

The growth of inter-regional trade in luxury goods (silk and cotton textiles, porcelain, spices, precious metals and gems, slaves, exotic animals) was encouraged by significant innovations in previously existing transportation and commercial technologies--including caravanserai, compass use, the astrolabe, larger ship

Hope this helped!!!