What is the land bridge theory based on?

The land bridge theory, also known as the Beringia theory, posits that during the last Ice Age, a land bridge emerged between Asia and North America due to lowered sea levels. This land bridge, known as Beringia, allowed humans and animals to migrate from Siberia to Alaska. The theory suggests that this migration led to the peopling of the Americas. Archaeological and genetic evidence supports this hypothesis, indicating that the first inhabitants of the Americas likely arrived via this route.