Final answer:
The Laetoli footprints, discovered by Mary Leakey and probably made by Australopithecus afarensis, show a parallel big toe and clear arch, indicative of bipedalism. Option C is correct.
Step-by-step explanation:
The Laetoli footprints are a significant paleoanthropological discovery that supports the conclusion that Australopithecus was bipedal. These footprints were discovered by English paleoanthropologist Mary Leakey in the 1980s and are estimated to be about 3.5 million years old.
The footprints were found in East Africa at the site of Laetoli and are likely to have been made by Australopithecus afarensis.
Analysis of the footprints reveals key characteristics that indicate bipedalism. The prints show a clear arch and a parallel (not divergent) big toe, which are both critical anatomical features for bipedal locomotion.
Specifically, the parallel big toe helps in transmitting weight during the step phase of walking, and the clear arch aids in absorbing the shock that comes with bipedal walking. These features are instrumental in supporting the weight of the body during upright walking.
Therefore, the correct answer to how the Laetoli footprints support the conclusion that Australopithecus was bipedal is C) The footprints show a parallel big toe, which is a characteristic of bipedalism. This is in contrast to a divergent big toe, which is found in non-bipedal primates and aids in grasping branches while climbing.