Final answer:
The two migration theories most scientists use to explain the origin of modern humans are the out of Africa model and the multiregional evolution model.
Step-by-step explanation:
The two migration theories most scientists use to explain the origin of modern humans are the out of Africa model and the multiregional evolution model.
The out of Africa model suggests that modern humans emerged in Africa and then expanded out of Africa to replace all other human species. The multiregional evolution model proposes that Homo sapiens evolved from Homo erectus in multiple places around the same time.
Both theories have supporting evidence, but the question of which theory is correct is still debated among scientists.