Before You Begin
Question #45481
The Question
Pollen grains are frequently recovered as well-preserved microfossils in geological sediments, acting as 'evolutionary fossil traps'. Which of the following statements INCORRECTLY describes the biological and chemical principles behind this persistence?
Options
- A.
A. The outer layer of the pollen grain is composed of sporopollenin, which is highly resistant to strong acids, alkalis, and high temperatures.
- B.
B. The long-term persistence of the pollen wall is strictly dependent on anaerobic, low-moisture sedimentary environments, because sporopollenin is rapidly degraded by aerobic microbial enzymes.
- C.
C. While the exine remains intact to serve as a geological marker, the inner pecto-cellulosic intine is susceptible to standard enzymatic degradation.
- D.
D. Sporopollenin is absent at specific prominent apertures called germ pores, yet the overall chemical inertness of the exine allows it to bypass the detritus food chain.
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
Sporopollenin|Decomposition Rate Modifiers|Ecosystem
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the general environmental conditions required to halt decomposition (anaerobiosis, low moisture) with the specific, inherent chemical inertness of sporopollenin.
The trap lies in a 'Common Half-Truth'—attributing sporopollenin's survival to environmental decomposition modifiers rather than its absolute, inherent resistance to all known microbial enzymes.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Pollen Wall Chemistry |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |