Answer:
Mantaro River
Explanation:
The source of the Amazon River has been attributed to the headwaters of three different Peruvian rivers in the high Andes: the Marañón, the Apurímac, and the Mantaro. Explorers and scholars have identified each of the three rivers as being the source of the Amazon under one of the three definitions.
An example is the president vetoing a law that Congress passes. He can refuse to sign a bill.
One way would be to limit who can receive a passport or visa to travel to another country and another would be at the entrance to the country they may not be admitted for example due to inadequate funds to live. In my case, when I travelled by bus from Costa Rica to Panama, the Panamanian authorities required that I either have a ticket out of the country or a return ticket back to San Jose, Costa Rica.
