Final answer:
The oldest suggested possible hominids dating back close to 6 million years ago are classified as Sahelanthropus tchadensis, Ardipithecus ramidus, and Ardipithecus kadabba. However, whether Sahelanthropus tchadensis is an ancestor of modern humans is uncertain.
Step-by-step explanation:
The oldest suggested possible hominids dating back close to 6 million years ago are classified as Sahelanthropus tchadensis, a species discovered in 2001-2002. However, it is uncertain whether this species is an ancestor of modern humans. Other early hominin species include Ardipithecus ramidus and Ardipithecus kadabba, which were bipedal and lived around 5.6 million years ago.