Final answer:
The skeleton of Lucy's baby indicates that Australopithecus afarensis was adapted for both arboreal and bipedal movement, with long arms and curved fingers/toes for climbing, and a pelvis shaped for upright walking.
Step-by-step explanation:
The skeleton of Lucy's baby reveals that Australopithecus afarensis had a combination of features suggesting both tree-dwelling and bipedal locomotion. While they had long arms and curved fingers and toes typical of organisms that hang from branches, their pelvic structure resembled that of modern humans, implying they could also walk upright. The morphology of their limbs and pelvis suggests that while A. afarensis may have been capable of walking on two legs, their movement was not identical to that of modern humans.