Final answer:
Genomic studies confirm that Neanderthals did not share a common ancestor with modern humans, but they did interbreed with them. Neanderthals had a larger brain size than modern humans, and this difference in brain organization may have been a survival adaptation.
Step-by-step explanation:
Genomic studies of Neanderthals, modern humans, and chimpanzees have confirmed that Neanderthals did not share a common ancestor with modern humans, but they did interbreed with them. DNA evidence shows that early humans and Neanderthals interbred and that some modern human populations have Neanderthal DNA. However, it is important to note that Neanderthals had a larger brain size than modern humans, but it does not necessarily mean they were more intelligent. The difference in brain organization between the two species suggests different areas of the brain were emphasized for survival adaptations.