which of the following has not been proposed as a model to explain the origin of modern homo sapines? a. an origin in africa, followed by migration to other areas where indigenous premodern populations were replaced. b. an origin in africa, followed by migration to other areas where both interbreeding and replacement occurred. c. several origins in different areas with where modern forms evolved from local regional populations. d. separate origins in africa and australia with migrations from both these areas to displace all other populations.