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Question #47409
The Question
The evolutionary transition to bipedalism in hominids required a structural remodeling of the pelvic girdle, creating a mechanical trade-off with increasing cranial capacities. In modern human females, the weight-bearing articulation of this girdle is highly susceptible to fractures during late adulthood. Which of the following statements regarding this anatomical and pathological integration is INCORRECT?
Options
- A.
The acetabulum is a cavity formed by the fusion of the ilium, ischium, and pubis, which articulates with the head of the femur to support vertical weight distribution.
- B.
The evolutionary expansion of cranial capacity in the genus Homo created an 'obstetrical dilemma' due to the narrow pelvic morphology required for efficient bipedal locomotion.
- C.
Post-menopausal structural failures in the femoral neck are exacerbated by a decline in estrogen levels, a hormone that normally stimulates osteoclastic resorption of the bone matrix.
- D.
Osteoporosis is an age-related disorder characterized by decreased bone mass and microarchitectural deterioration, increasing the fragility of the appendicular skeleton.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Pelvic_Girdle|Bipedalism|Weight_Bearing|Osteoporosis
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the NCERT line 'decreased levels of estrogen is a common cause of osteoporosis' but fail to grasp the cellular mechanism.
The trap relies on Functional Confusion/Word-Play: swapping 'inhibits' with 'stimulates'.
If estrogen stimulated osteoclasts, a drop in estrogen would logically increase bone mass, which contradicts the pathology of osteoporosis.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Locomotion and Movement - Class 11 |
| Concept | Osteoporosis vs. Arthritis |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |