When initially observing the mysterious glowing waters of Mosquito Bay in Puerto Rico, researchers believed the phenomenon resulted from chemical...
GMAT Expression of Ideas : (Expression) Questions
When initially observing the mysterious glowing waters of Mosquito Bay in Puerto Rico, researchers believed the phenomenon resulted from chemical pollution or artificial lighting systems. ______ detailed analysis revealed that microscopic organisms called dinoflagellates produce this natural bioluminescence when disturbed by movement.
Which choice completes the text with the most logical and precise word or phrase?
However,
For instance,
Therefore,
Subsequently,
Step 1: Decode and Map the Passage
Passage Analysis Table
| Text from Passage | What it says | What it does | What it is |
|---|---|---|---|
| "When initially observing the mysterious glowing waters of Mosquito Bay in Puerto Rico, researchers believed the phenomenon resulted from chemical pollution or artificial lighting systems." | Researchers initially thought glow = pollution/artificial lights | Introduces researchers' initial belief about the phenomenon | Initial hypothesis/assumption |
| "[MISSING TRANSITION]" | Missing logical connector | ||
| "detailed analysis revealed that microscopic organisms called dinoflagellates produce this natural bioluminescence when disturbed by movement." | Analysis showed dinoflagellates cause natural bioluminescence | Presents what analysis actually found | Corrective finding/evidence |
Passage Architecture & Core Elements
Visual Structure Map:
Initial Belief (pollution/artificial lights) → [Missing connector] → Actual Finding (natural dinoflagellates)
Main Point: Scientific analysis corrected researchers' initial misconception about the cause of bioluminescent waters.
Argument Flow: The passage presents researchers' initial assumption about the cause of glowing waters, then reveals through analysis what actually causes the phenomenon. The structure moves from incorrect assumption to corrected understanding.
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
- Looking at our analysis, we have researchers believing one thing initially, then analysis revealing something completely different
- The relationship needed is a contrast - the blank needs to signal that what follows contradicts or corrects what came before
- The right answer should indicate that the analysis revealed something opposite to the initial belief
However,
✓ Correct
- Creates the needed contrast between initial belief and actual finding
- Signals that the analysis revealed something different from what researchers first thought
- Matches our prethinking perfectly
For instance,
✗ Incorrect
- Would introduce an example of the initial belief
- Makes no logical sense as detailed analysis is not an example of pollution or artificial lighting
Therefore,
✗ Incorrect
- Would suggest the analysis resulted from or confirmed the initial belief
- Creates the opposite logic by implying the dinoflagellates finding supports the pollution theory
Subsequently,
✗ Incorrect
- Only shows time order without indicating the nature of the relationship
- Does not capture that the analysis contradicted the initial belief