Final answer:
The Clovis people may have contributed to the extinction of giant species, but rapid temperature rise at the end of the last ice age was also a factor. The homogeneity of the North American Clovis culture supports the theory that they were the first people to inhabit the Americas. There is also evidence of a pre-Clovis culture that extends back further than 13,200 years before present.
Step-by-step explanation:
An alternate hypothesis suggests that rapid temperature rise at the end of the last ice age was the primary culprit for the extinction of the giant species present during the Clovis period. However, it is plausible that both human intervention and climate change were factors.
The extensive homogeneity of the North American Clovis culture supports the theory that they were the first people to inhabit the Americas. Archaeologists theorize that the Clovis peoples came over the land bridge from Asia and spread through much of North America.
There is growing evidence of an extensive pre-Clovis culture, evidenced by a pre-Clovis technology based on gathering, hunting, and fishing. Pre-Clovis sites are located below the Clovis period occupation, indicating an occupation that extends back further than 13,200 years before present.