Members of the genus homo (particularly homo erectus) were the first hominids to migrate out of africa. according to the text, the most probable reason for their leaving was:
a. their "reproductive success" (better adapted, they reproduced more, resulting in over- crowding in africa, forcing some populations out)
b. natural human curiosity about other places
c. seeking more tropical climates (year-round growing seasons) for their plan-based diets
d. they were out-competed by the australoithecines
e. none of the above (just like the australopithecines, they never left africa)