Final answer:
Human hunting played a significant role in the extinction of Pleistocene megafauna, although climate change may have also played a part.
Step-by-step explanation:
Humans played a significant role in the extinction of Pleistocene megafauna (large mammals). The timing of the extinctions correlated with the arrival of humans, suggesting that human hunting contributed to their decline. While climate change may have affected the availability of food and habitat for some species, research has shown that human hunting was a primary factor in the extinctions.