Complex sentence: The exact dates and routes of the peopling of the Americas are the subject of an ongoing debate, but it is clear that by 16,000 years ago the glacial melt allowed people to move by land south and east out of Beringia, and into Canada.
Split into simpler sentences: The exact dates and routes of the peopling of the Americas are the subject of an ongoing debate. By 16,000 years ago the glacial melt allowed people to move by land south and east out of Beringia, and into Canada.