Peoples occupied North America before the arrival of the (1)______ European in the 15th century have long been known as Indians because (2)______ of the belief prevalent at time of Columbus that the Americas were the (3)______ outer reaches of the Indies. Most scholars agree that Native Americans came into the Western Hemisphere from Asia by the Bering Strait in a (4)______ series of migrations. From Alaska they spread to the east and south. (5)______ Several separate waves of migration are said to count for the many native (6)______ linguistic families, while the common origin used to explain the physical (7)______ characteristics that Native Americans have in common--Mongoloid features, coarse, straight, black hair, dark eyes, sparse body hair, and a skin colour range from yellow-brown to reddish brown. Many scholars (8)______ accept evidence of Native American existence in the Americas back more than 25,000 years. In pre-Columbian times the Native American population of the area north of Mexico is estimated to be between one and (9)______ two million. From prehistoric times until recent historic times there were roughly about six major cultural areas, excluding that of the Arctic i. e. , (10)______ Northwest Coast, Plains, Plateau, Eastern Woodlands, and Southwest. Information about particular groups can be found in separate articles and in separate biographies and subject articles.