Final answer:
The earliest bipedal hominids were discovered in Africa, with significant findings including footprints at Laetoli and fossils of species like Ardipithecus.
Step-by-step explanation:
The earliest bipedal hominids are discovered on the continent of Africa. This is supported by the significant discovery made by the English paleoanthropologist Mary Leakey in the 1980s. She found a trail of footprints made by bipedal hominids at the site of Laetoli in East Africa, dating back about 3.5 million years ago. These footprints were likely left by Australopithecus afarensis, one of the early hominins known to have walked upright. Additional fossil evidence from species such as Ardipithecus dating back to about 4.4 million years ago, further supports Africa as the cradle of bipedal hominin evolution.