Final answer:
The most accepted theories on the arrival of the first people in the Americas are the Bering Land Bridge and coastal migration models, dating back to 20,000-14,000 BP, with pre-Clovis evidence suggesting even earlier human presence.
Step-by-step explanation:
Theories about the first people arriving in the Americas are supported by various sets of archaeological evidence. Two well-accepted theories are the Bering Land Bridge and coastal migration models, which suggest that humans migrated from Asia to the Americas around 20,000-14,000 BP (before present). Controversially, the Solutrean hypothesis proposes a European origin, but genetic studies largely discredit this. Some sites like Monte Verde in Chile suggest an even earlier human presence dating back to 12,000 BCE, predating the Clovis culture. Furthermore, discoveries of pre-Clovis sites indicate an even earlier occupation and continuous revisions in our understanding of the timing of human migrations to the Americas.