Which of the following aided the expansion of human populations throughout North America?
A. the invention of the wheel
B. abundant big-game animals
C. the domestication of primitive horses
D. widespread slash-and-burn horticulture
E. raised-field cultivation
Question 2
Although there is now evidence that several human groups colonized the Americas, possibly using different routes, those that crossed over through Beringia to reach the Americas did so
A. because they were fleeing from warlike Cro-Magnon groups.
B. in order to take advantage of large flint deposits in South America.
C. following herds of big-game animals (woolly mammoths, especially).
D. because they were gradually forced into new territories by the expansion of more advanced agricultural groups in Asia.
E. in their search for colder climates, because these Neandertals were adapted to cold weather.
Four hypotheses on how populations might relate to one another along an environmental gradient.
Human cavity
A colorized image of human chromosomes
Human Genetic Disorders
G-banded karyotype of a normal human male
Sensory receptors in human skin.