Give three reasons why
trade became easier under
the Qin.

Road and canal systems enabled internal trade in the Qin's newly conquered territories. The Qin pioneered foreign trade through the establishment of the Marine Silk Road, a sea route starting at Guangzhou on the Pearl River that flows out to the South China Sea. This enabled trade from China initially along the Indian Ocean and Arabian Sea, and it's the world's oldest known maritime trading route. The greatest development of this sea passage, and the land-based Silk Road into Central Asia, occurred in the subsequent Han, Sui, Tang and Song Dynasties. - https://classroom.synonym.com/economics-of-the-qin-dynasty-12082537.html