Final answer:
A feature shared by modern humans and lacking in other Homo species is the presence of a chin. This trait distinguishes Homo sapiens from other species such as Homo erectus, Homo habilis, and Homo floresiensis, even though other traits like brain size and tool use may overlap.
Step-by-step explanation:
One feature shared by modern humans and lacking in other Homo species is a chin. While features like a large brain, bipedalism, tool making, and having legs longer than arms are either common to certain other Homo species or to primates in general, the presence of a pronounced chin is unique to modern humans, Homo sapiens. Other Homo species like Homo erectus and Homo habilis had a larger brain and made tools, but did not possess a chin. Homo floresiensis also had a lack of a chin and different bipedal locomotion characteristics. Scientific criteria for the classification of the genus Homo include the brain size over 600 cc, tool use, and fully adapted feet for walking, among other characteristics.