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Question #46177
The Question
A marine biologist observes two pelagic fishes—one belonging to Class Chondrichthyes and the other to Class Osteichthyes—trapped in a stationary net that prevents forward locomotion. The surrounding water experiences a mild drop in dissolved oxygen. Which of the following statements correctly predicts their physiological response and the underlying anatomical reason?
Options
- A.
The Osteichthyes maintains ventilation via opercular pumping to supply O2 as the terminal electron acceptor, while the Chondrichthyes faces systemic failure due to the lack of an operculum for active water pumping.
- B.
The Chondrichthyes utilizes its air bladder as an accessory respiratory organ to maintain the terminal electron acceptor, while the Osteichthyes succumbs to hypoxia.
- C.
Both fishes will maintain equal metabolic rates because the countercurrent mechanism in their gills operates passively and independently of opercular movement or forward locomotion.
- D.
The Osteichthyes faces rapid metabolic failure because its ctenoid scales prevent cutaneous respiration, whereas the Chondrichthyes utilizes placoid scales for gas exchange.
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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
Chondrichthyes|Osteichthyes|Terminal_Electron_Acceptor|Gills
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize 'Chondrichthyes lack an operculum and air bladder' as isolated morphological facts.
This question forces the synthesis of that NCERT fact with its physiological consequence (obligate ram ventilation vs. buccal pumping) and its ultimate cellular impact (availability of O2 as the terminal electron acceptor).
The trap lies in confusing the buoyancy function of the air bladder with the ventilation function of the operculum.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Animal Kingdom - Class 11 |
| Concept | Chondrichthyes vs. Osteichthyes Buoyancy |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |