What change occurred in the limb structure of hominins?

The correct answer highlights a significant evolutionary adaptation in hominins, which refers to the lineage of species that includes modern humans and our immediate ancestors. As hominins evolved, one of the key changes observed in their limb structure was the development of shorter arms and longer legs.

This modification is closely associated with bipedalism, the ability to walk on two legs. Longer legs provide enhanced efficiency in travel over distances and are better suited for upright walking. In contrast, shorter arms reflect a reduced reliance on climbing and swinging in trees, which was more characteristic of earlier primates.

Overall, this change allowed hominins to adapt to savanna habitats, enabling them to cover greater distances for food and resources while also freeing their hands for tool use and manipulation, which are significant aspects of human evolution.