Some scientists think the first migrants to the Americas came by boat.
Some scientists think the first migrants to the Americas came by crossing a land bridge.
Most scientists believe the first migrants came to North America from Asia.
Explanation:
In the past century there has been a consensus about the migration of people to the Americas. It was commonly accepted that the first humans in the Americas came at the end of the last Ice Age. The hypothesis says that they came by a land bridge that existed between North America and Eurasia, and that their origin was from what is now Siberia, or rather from central and eastern North Asia. This has been and still is the most accepted hypothesis.
In the past couple of decades though the view on this hypothesis started to change. Lot of new evidence emerged that suggest that this hypothesis is flawed so more and more scientist are not supporting it.
There has been new sites where remains of human activities have been found and they predate what was suggested by tens of thousands of years. The genetic studies are suggesting that there are groups of people that originated from Polynesia and from Northern Europe. In Mesoamerica and in the Amazon there are multiple groups of people that have Polynesia genes, while some Native Americans in the eastern part of North America have European genes. This means that people migrated not just from Asia, but also from Northern Europe (by a boat or through a land bridge), and by a boat though the Pacific Ocean.
Answer: In the context of American constitutional law, the definition of republic refers specifically to a form of government in which elected individuals represent the citizen body and exercise power according to the rule of law under a constitution, including separation of powers with an elected head of state.
