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Question #46485
The Question
In the context of hominid evolution, an increase in cranial capacity requires synchronized developmental changes. Suppose a temporal regulatory mutation causes an accelerated rate of neural progenitor cell division but simultaneously triggers premature ossification of cranial sutures (craniosynostosis), leading to developmental failure. Which of the following statements regarding this biological scenario is INCORRECT?
Options
- A.
The evolutionary expansion of the hominid brain is constrained by the need for coordinated transcriptional regulation across interacting tissue layers.
- B.
The mutation likely altered regulatory elements such as enhancers, shifting the transcriptional boundaries of genes governing neural proliferation.
- C.
The premature ossification serves as a positive selection pressure by providing early mechanical protection to the rapidly expanding neural mass.
- D.
This demonstrates that an isolated upregulation of neural progenitor division is evolutionarily futile without a corresponding delay in skeletal maturation.
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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
Transcriptional Unit Boundaries|Hominid Cranial Capacity
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often reflexively associate 'ossification' and 'protection' with an evolutionary advantage (positive selection).
The trap relies on failing to recognize the temporal constraint of development: structural integrity (bone fusion) must be strictly delayed to accommodate neural proliferation.
This tests the understanding that evolutionary adaptations require coordinated, multi-tissue transcriptional regulation, not just isolated trait enhancement.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Evolution - Class 12 |
| Concept | Hominid Cranial Capacity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |