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Question #46145
The Question
Earthworms (Pheretima) possess a closed circulatory system with hemoglobin. However, during severe environmental hypoxia, they experience rapid systemic respiratory failure compared to vertebrates. Which of the following structural trade-offs best explains this physiological limitation?
Options
- A.
Hemoglobin is dissolved directly in the blood plasma, lacking the erythrocyte-mediated intracellular pH-buffering required for an efficient Bohr effect.
- B.
The blood glands in the 4th, 5th, and 6th segments produce hemoglobin that exhibits a leftward shift in the oxygen dissociation curve during high tissue pCO2.
- C.
The lack of a specialized respiratory surface prevents the establishment of a steep partial pressure gradient, rendering the closed circulatory system ineffective.
- D.
Hemoglobin in annelids is packaged within specialized amoeboid corpuscles that lack carbonic anhydrase, severely limiting CO2 transport.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Hemoglobin|Closed_Circulatory_System|Gases_Exchange
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating Structural Organization in Animals with Human Physiology.
Students memorize that earthworms have hemoglobin and a closed circulatory system, but often overlook the functional consequence of the NCERT line 'haemoglobin is dissolved in blood plasma'.
The trap tests the physiological necessity of erythrocytes for an efficient Bohr effect.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Animal Kingdom - Class 11 |
| Concept | Annelida Circulatory System |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |