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  The Pleistocene Epoch marks the Ice Age, during which glaciers expanded and contracted multiple times.
As sea levels dropped during glaciation, the Bering Land Bridge (Beringia) became exposed, connecting Asia and North America. - 
  
  Archaeological evidence suggests that populations in northeastern Siberia started to inhabit Beringia.
These people are believed to have adapted to the harsh, cold environment of the region. - 
  
  The Last Glacial Maximum (LGM) saw glaciers reach their peak, causing sea levels to drop significantly.
Beringia expanded, providing a land route between Asia and North America. However, the glaciated areas in North America may have made further migration difficult during this period. - 
  
  
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  Genetic evidence suggests that humans remained in Beringia for thousands of years, isolated from both Asia and North America.
This "Beringian Standstill Hypothesis" posits that populations lived in Beringia for some time before migrating further into North America when the ice sheets receded. - 
  
  
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  As the glaciers began to retreat, an ice-free corridor opened in present-day Canada, allowing human migration into North America.
This corridor is believed to have provided the first route southward for people from Beringia. - 
  
  
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  Archaeological sites, such as the Buttermilk Creek Complex in Texas, suggest human presence in North America as early as 15,000 to 14,000 years ago.
These people likely followed large game like mammoths and bison. - 
  
  The Clovis culture is widely considered one of the earliest identifiable groups in North America, known for their distinctive spear points.
Clovis sites appear around 13,000 years ago, suggesting the widespread migration of early Americans across the continent. - 
  
  As the Ice Age ended, sea levels rose, submerging the Bering Land Bridge.
The populations that had crossed into the Americas were now cut off from Asia, solidifying the distinct development of indigenous cultures in the New World. - 
  
  
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  In recent decades, genetic, linguistic, and archaeological research has provided new insights into the timing and routes of human migration into the Americas.
Some studies suggest possible alternative migration routes, such as coastal pathways along the Pacific Ocean.