Before You Begin
Question #46302
The Question
A dicotyledonous angiosperm is found thriving in an ecosystem that characteristically exhibits an inverted pyramid of biomass. Transverse sectioning of its mature stem reveals poorly developed primary xylem and vascular bundles lacking active intrafascicular cambium. Which of the following statements best justifies this anatomical adaptation in relation to its habitat?
Options
- A.
The suppression of secondary growth prevents the formation of dense, lignified wood, acting as an evolutionary trade-off to maintain buoyancy in an aquatic environment.
- B.
The absence of cambium allows the plant to rapidly complete its life cycle, which directly causes the inverted biomass pyramid observed in this ecosystem.
- C.
The plant relies entirely on secondary phloem for mechanical support since the primary xylem is highly reduced to minimize water resistance.
- D.
The closed vascular bundles are an adaptation to prevent the entry of excess water into the pith, thereby avoiding cellular lysis in hypotonic conditions.
Check Your Answer
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
Vascular Bundle|Inverted Biomass Pyramids|Evolutionary Constraints
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Decoding ecological clues to infer anatomical adaptations.
Students must first recognize 'inverted biomass pyramid' as NCERT code for an 'aquatic ecosystem'.
Then, they must bridge Class 12 Ecology with Class 11 Plant Anatomy to understand that aquatic dicots suppress secondary growth (cambial activity) because lignified secondary xylem (wood) is dense and counteracts the buoyancy required for survival in water.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Anatomy of Flowering Plants - Class 11 |
| Concept | Vascular Bundle Openness |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |