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Question #46122
The Question
A researcher applies a highly specific conduction inhibitor locally to a single mid-body segmental ganglion of an earthworm (Pheretima) and, in a separate experiment, completely inhibits the Sinoatrial (SA) node of a human heart. Which of the following best describes the contrasting physiological fallout based on their structural organization?
Options
- A.
The earthworm exhibits localized functional loss due to decentralized metameric control, whereas the human heart loses its primary synchronized cardiac cycle due to the failure of its centralized myogenic pacemaker.
- B.
Both organisms will experience complete systemic failure because both rely on a centralized neural network to initiate rhythmic muscular contractions.
- C.
The earthworm will experience systemic paralysis due to its continuous ventral nerve cord, while the human heart will maintain normal ventricular rhythm due to the independent autorhythmicity of the Purkinje fibers.
- D.
The earthworm's metameric syncytium will propagate the inhibition throughout its body, whereas the human heart's compartmentalized chambers will confine the conduction failure strictly to the right atrium.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Cardiac_Cycle_Temporal_Precision|Metamerism|Structural_Organisation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Understanding the evolutionary trade-off between decentralized metameric control (resilience to localized damage) and centralized syncytial conduction (high-efficiency, synchronized output but vulnerable to a single point of failure).
The trap lies in confusing the heart's physical compartmentalization (4 chambers) with its electrical nature (a unified functional syncytium dependent on the SA node).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Animal Kingdom - Class 11 |
| Concept | Segmentation vs. Metamerism |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |