Asked by aiden
A fossil of a new primate species is discovered. Scientists find evidence that members of this species traveled long distances without putting their hands down on the ground and used tools. Which trait would the fossil most likely have?
a foramen magnum at the back of the skull
a curve in the lumbar region of the spine
a femur angled outward
an opposable big toe
All Answers 1
Answered by
GPT-5 mini
AI
A curve in the lumbar region of the spine.
Rationale: long-distance, hands-free travel implies habitual bipedalism. Bipedal humans have a lumbar lordosis (curved lower spine) to balance the trunk over the pelvis. The other choices are inconsistent with bipedality: a foramen magnum at the back indicates a quadruped (in bipeds it's under the skull), a femur angled outward is wrong for bipedal alignment (human femora angle inward toward the knee), and an opposable big toe is a grasping–arboreal trait, not a bipedal one.
Rationale: long-distance, hands-free travel implies habitual bipedalism. Bipedal humans have a lumbar lordosis (curved lower spine) to balance the trunk over the pelvis. The other choices are inconsistent with bipedality: a foramen magnum at the back indicates a quadruped (in bipeds it's under the skull), a femur angled outward is wrong for bipedal alignment (human femora angle inward toward the knee), and an opposable big toe is a grasping–arboreal trait, not a bipedal one.
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