<span>Po River. Po River, Latin Padus, longest river in Italy, rising in the Monte Viso group of the Cottian Alps on Italy's western frontier and emptying into the Adriatic Sea in the east after a course of 405 miles (652 km)</span>
Restrict the flow of immigrants.
<em>Hope this helped!</em>
<em>- Uaiska</em>
Answer: The answer is "periodization."