Final answer:
Bipedality evolved in hominins for reasons such as freeing hands, increasing energy efficiency, and improving thermoregulation. This allowed humans to engage in greater complexity of tool use relative to apes.
Step-by-step explanation:
Bipedality evolved in hominins due to several hypotheses. These include freeing hands to carry tools, food, or offspring, increasing energy efficiency, and improving thermoregulation. The evolution of bipedality may have facilitated greater complexity of tool use in humans relative to apes by providing the ability to use hands more effectively and freeing them from locomotion tasks.