What is the leading theory about how early humans arrived on the American continents?
(1 point)
Responses
A. They walked from Africa to South America when those two continents were part of the same landmass.
B. They walked from Asia to North America over a strip of land that has since been covered by the ocean.
C. They sailed in large ships from Australia to North America.
D. They canoed from Antarctica to South America when the climate there became too harsh.