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Question #135620
The Question
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In a pelagic marine ecosystem, the pyramid of biomass is inverted, yet the pyramid of energy remains strictly upright. Reason (R): The instantaneous standing crop of phytoplankton is lower than that of zooplankton due to a rapid turnover rate, but their net primary productivity is higher, ensuring continuous energy flow. In the light of the above statements, choose the most appropriate answer from the options given below:
Options
- A.
Both (A) and (R) are correct and (R) is the correct explanation of (A)
- B.
Both (A) and (R) are correct but (R) is not the correct explanation of (A)
- C.
(A) is correct but (R) is not correct
- D.
(A) is not correct but (R) is correct
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
Inverted Biomass Pyramids|Standing Crop quantification|Productivity Ratios
Why This Question Is Tricky
Examiner Levers
Logical Assertion
Tests the causal relationship between two true statements.
Difficulty Boost : +4Common Mistakes
Conceptual Pivot: The trap lies in confusing 'Standing Crop' (a static snapshot of living mass at a given time) with 'Net Primary Productivity' (the dynamic rate of biomass synthesis).
Students often mistakenly believe that a smaller producer biomass cannot sustain a larger consumer biomass, failing to account for the high turnover rate (rapid reproduction and immediate consumption) of phytoplankton.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Ecosystem - Class 12 |
| Concept | Inverted Biomass Pyramids |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |