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Question #46875
The Question
Annelids (e.g., earthworms) possess a closed circulatory system, whereas Arthropods (e.g., insects), despite having significantly higher metabolic demands for activities like flight, possess an open circulatory system. Which of the following statements correctly explains the evolutionary and physiological basis for this divergence?
Options
- A.
The closed system in earthworms is primarily an adaptation to minimize the metabolic cost of pumping blood, whereas the open system in insects maximizes pumping efficiency.
- B.
Insects decoupled their respiratory and circulatory systems via a tracheal network, rendering the energetically expensive high-pressure closed system redundant for oxygen delivery.
- C.
The open circulatory system in insects maintains a higher systemic hydrostatic pressure than the closed system of annelids, ensuring rapid nutrient delivery to flight muscles.
- D.
Earthworms require a closed system because their blood lacks respiratory pigments, whereas insect hemolymph contains abundant hemocyanin for rapid oxygen transport.
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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
Earthworm Circulatory Closed System|Natural Selection Directionality|Evolution
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume an evolutionary linear progression where 'higher metabolic rate' (like insect flight) strictly requires a 'more advanced' closed circulatory system.
The trap lies in failing to integrate respiratory anatomy (tracheal system) with circulatory physiology.
By decoupling oxygen transport from hemolymph circulation, insects bypass the need for a high-pressure closed system, revealing a profound example of evolutionary bioenergetic trade-offs.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Structural Organisation in Animals - Class 11 |
| Concept | Earthworm Circulatory Closed System |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |