Paleontologists studying rock formations have observed that fossils in certain layers show extensive degradation and poor preservation. Biological rem...
GMAT Information and Ideas : (Ideas) Questions
Paleontologists studying rock formations have observed that fossils in certain layers show extensive degradation and poor preservation. Biological remains generally fossilize well when buried quickly in fine sediments that exclude oxygen and prevent bacterial decay. Consequently, the degraded fossils were probably ______
Which choice most logically completes the text?
formed during a period of unusual geological activity in the region.
representative of species that lived in particularly harsh environmental conditions.
exposed to oxygen and bacterial action during their formation process.
buried in coarser sediments that allowed for better preservation.
Step 1: Decode and Map the Passage
Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| 'Paleontologists studying rock formations have observed that fossils in certain layers show extensive degradation and poor preservation.' |
|
| 'Biological remains generally fossilize well when buried quickly in fine sediments that exclude oxygen and prevent bacterial decay.' |
|
| 'Consequently, the degraded fossils were probably ______' |
|
Provide Passage Architecture & Core Elements
Main Point: Since we know what conditions create good fossil preservation, we can infer what likely caused poor preservation in these degraded fossils.
Argument Flow: The passage presents a specific observation about degraded fossils, then provides the general principle for good fossil preservation, and finally asks us to make a logical inference about what probably caused the poor preservation we observed.
Step 2: Interpret the Question Precisely
This is a fill-in-the-blank question asking us to choose the best logical connector. The answer must create the right relationship between what comes before and after the blank.
Step 3: Prethink the Answer
- We know that good preservation happens when fossils are buried quickly in fine sediments that exclude oxygen and prevent bacterial decay
- Since these fossils show extensive degradation and poor preservation, they must have experienced the opposite conditions
- The right answer should explain that these degraded fossils were probably exposed to oxygen and bacterial action during formation
formed during a period of unusual geological activity in the region.
✗ Incorrect
- Suggests the fossils formed during unusual geological activity
- This does not connect to the preservation principle we learned about
representative of species that lived in particularly harsh environmental conditions.
✗ Incorrect
- Claims these represent species from harsh living environments
- This confuses living conditions with preservation conditions
exposed to oxygen and bacterial action during their formation process.
✓ Correct
- States they were exposed to oxygen and bacterial action during formation
- This directly applies our preservation principle in reverse
buried in coarser sediments that allowed for better preservation.
✗ Incorrect
- Says they were buried in coarser sediments that allowed better preservation
- This contradicts what we observe since these fossils show poor preservation