Answer: They were a transition between human beings and apes.
Step-by-step explanation:
Australopithecus is an ape which is capable of living on trees. These animal like human can also walk on two feet.
The fossils that are found shows the transition species that lived at the time when the ancestors were shifting from trees to ground.
The fossils show that it was a transition between apes and humans living on trees and on land.