Final answer:
The evidence supporting the hypothesis of multiple species of hominins existing at the same time is strong. This evidence challenges the idea of a linear progression from early hominins to modern humans.
Step-by-step explanation:
The evidence supporting the hypothesis that multiple species of hominins existed at the same time is strong.
In the past, scientists believed that the order of hominin fossils from oldest to youngest would demonstrate the course of evolution.
However, with the discovery of many new fossils, it is clear that there were often multiple species alive at any one time.
For example, fossils show that Australopithecus and H. erectus lived at the same time.
This evidence challenges the idea of a linear progression from early hominins to modern humans.