Marine biologist Dr. James Chen and his research team have been studying the impact of ocean acidification on coral reef...
GMAT Craft and Structure : (Structure) Questions
Marine biologist Dr. James Chen and his research team have been studying the impact of ocean acidification on coral reef ecosystems in the Pacific. The team hypothesizes that decreasing pH levels are significantly reducing coral calcification rates, threatening the structural integrity of entire reef systems. For instance, Australia's Great Barrier Reef has experienced unprecedented coral bleaching events in recent years, with scientists documenting massive die-offs linked to changing ocean chemistry. Through continuous monitoring of water chemistry and coral growth at fifteen reef sites over a seven-year period, the researchers have been tracking the relationship between pH fluctuations and coral health indicators.
Which choice best states the function of the underlined sentence in the overall structure of the text?
To establish the research hypothesis that guided the investigation
To provide a concrete example that illustrates the team's hypothesis
To outline the specific methods used in the research study
To present the key conclusions drawn from the data analysis
Step 1: Decode and Map the Passage
Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| Marine biologist Dr. James Chen and his research team have been studying the impact of ocean acidification on coral reef ecosystems in the Pacific. |
|
| The team hypothesizes that decreasing pH levels are significantly reducing coral calcification rates, threatening the structural integrity of entire reef systems. |
|
| For instance, Australia's Great Barrier Reef has experienced unprecedented coral bleaching events in recent years, with scientists documenting massive die-offs linked to changing ocean chemistry. |
|
| Through continuous monitoring of water chemistry and coral growth at fifteen reef sites over a seven-year period, the researchers have been tracking the relationship between pH fluctuations and coral health indicators. |
|
Provide Passage Architecture & Core Elements
Main Point: Dr. Chen's team is studying how ocean acidification damages coral reefs, with the Great Barrier Reef serving as a prime example of this environmental threat.
Argument Flow: The passage establishes research context, presents the team's hypothesis about pH effects on coral reefs, provides the Great Barrier Reef as concrete evidence supporting this hypothesis, and concludes by explaining their systematic approach to studying this relationship.
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
- The underlined sentence starts with 'For instance,' which signals an example
- It comes right after the hypothesis about pH levels damaging coral reefs
- The sentence provides a specific, real-world case - the Great Barrier Reef - that shows what the hypothesis predicts: coral damage from changing ocean chemistry
To establish the research hypothesis that guided the investigation
✗ Incorrect
- This suggests the sentence establishes the research hypothesis, but the hypothesis was already stated in the previous sentence
To provide a concrete example that illustrates the team's hypothesis
✓ Correct
- This perfectly matches our analysis
- The sentence provides a concrete example (Great Barrier Reef) that illustrates the team's hypothesis
- The 'For instance' transition clearly signals this is an example
To outline the specific methods used in the research study
✗ Incorrect
- This suggests the sentence outlines research methods, but it discusses the Great Barrier Reef situation, not research methodology
To present the key conclusions drawn from the data analysis
✗ Incorrect
- This suggests the sentence presents conclusions from data analysis, but this is still in the setup phase describing the research context