Final answer:
Scientists determined that Tumai walked on two legs by analyzing its morphology and looking for characteristics such as the length of the arms and legs, the shape of the feet, and the angling of the femur bone.
Step-by-step explanation:
Scientists determined that Tumai walked on two legs by analyzing several aspects of its morphology. They looked for characteristics such as the length of the arms and legs, the shape of the feet, and the angling of the femur bone. Based on these factors, scientists concluded that Tumai was a bipedal creature. For example, brachiators have long arms, while leapers have long legs, but Tumai had legs of equal length.