The country has no import and export goods. The country development, developing more slowly than the original because the item could not be sent to scoop up a pile of benefits from abroad.
Countries have import and export of goods. Poorer countries Develop more slowly than before because you can not export to seize the benefits from abroad.
The country has no import and export countries underdeveloped. Develop slower because it can't be exportable to assimilate the original benefits from abroad.