While researching a topic, a student has taken the following notes:Declining crop yields have become a significant problem across certain...
GMAT Expression of Ideas : (Expression) Questions
While researching a topic, a student has taken the following notes:
- Declining crop yields have become a significant problem across certain farmland areas in upstate New York.
- Cornell University researchers investigated this issue in 2021, focusing on soil chemistry changes.
- Over the past decade, these affected areas developed severely acidic conditions, with pH levels dropping below \(\mathrm{5.0}\).
- Such extreme acidity creates an environment where essential nutrients like nitrogen and phosphorus become unavailable to plant roots.
- Agricultural productivity suffers because typical food crops require nutrient absorption that acidic soil prevents.
- However, certain plants have adapted to thrive in these conditions—blueberries, for example, actually prefer acidic soil environments.
The student wants to describe the reason for declining crop yields in these areas. Which choice most effectively uses relevant information from the notes to accomplish this goal?
Crop yields declined because the highly acidic soil prevented plants from absorbing essential nutrients needed for growth.
Certain farmland areas became severely acidic over the past decade, leading to declining yields that were studied by Cornell researchers.
While most food crops cannot survive in acidic soil, some plants like blueberries can tolerate these conditions.
Soil with pH levels below \(5.0\) is considered highly acidic and poses challenges for agricultural productivity.
Step 1: Decode and Map the Passage
Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "Declining crop yields have become a significant problem across certain farmland areas in upstate New York." |
|
| "Cornell University researchers investigated this issue in 2021, focusing on soil chemistry changes." |
|
| "Over the past decade, these affected areas developed severely acidic conditions, with pH levels dropping below 5.0." |
|
| "Such extreme acidity creates an environment where essential nutrients like nitrogen and phosphorus become unavailable to plant roots." |
|
| "Agricultural productivity suffers because typical food crops require nutrient absorption that acidic soil prevents." |
|
| "However, certain plants have adapted to thrive in these conditions—blueberries, for example, actually prefer acidic soil environments." |
|
Provide Passage Architecture & Core Elements
Main Point: Declining crop yields in upstate New York farmland are caused by severely acidic soil conditions that prevent typical food crops from absorbing essential nutrients.
Argument Flow: The notes establish a clear problem and then walk through Cornell research findings that explain the cause. The soil became severely acidic over the past decade, which blocks essential nutrients from reaching plant roots. Since typical food crops need these nutrients to grow, their productivity suffers.
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
- Connect acidic soil conditions to the yield decline
- Explain the mechanism of how acidity prevents nutrient absorption
- Focus on the causal relationship rather than just describing facts
- Right answer should draw directly from the notes and explains the cause-and-effect relationship clearly
- Severely acidic soil makes essential nutrients unavailable to plant roots
- Typical food crops need these nutrients for growth
- Cannot thrive in these conditions, leading to declining yields
Crop yields declined because the highly acidic soil prevented plants from absorbing essential nutrients needed for growth.
- Directly explains the causal mechanism: acidic soil prevents nutrient absorption
- Uses relevant information from our notes about soil acidity and nutrient availability
- Focuses specifically on explaining the REASON for declining yields
Certain farmland areas became severely acidic over the past decade, leading to declining yields that were studied by Cornell researchers.
- Describes the timeline and mentions the research, but does not explain WHY yields declined
- More of a summary of what happened rather than an explanation of the cause
While most food crops cannot survive in acidic soil, some plants like blueberries can tolerate these conditions.
- Focuses on plants that CAN survive in acidic conditions rather than why typical crops cannot
- Does not explain the reason for declining yields in food crops
Soil with pH levels below \(5.0\) is considered highly acidic and poses challenges for agricultural productivity.
- Provides a definition of acidic soil and mentions challenges generally
- Does not explain the specific mechanism of how acidity causes yield decline