To better understand the burrowing habits of Alpheus bellulus (the tiger pistol shrimp), some studies have used resin casting to...
GMAT Information and Ideas : (Ideas) Questions
To better understand the burrowing habits of Alpheus bellulus (the tiger pistol shrimp), some studies have used resin casting to obtain precise measurements of the shrimps' burrows. Resin casting involves completely filling an empty burrow with a liquid plastic that hardens to create a three-dimensional model; however, recovering the model inevitably requires destroying the burrow. In their 2022 study, Miyu Umehara and colleagues discovered that an x-ray computed tomography (CT) scanner can accurately record a burrow's measurements both at a moment in time and throughout the entire burrow-building process, something that's impossible with resin casting because ______
Which choice most logically completes the text?
it can only be used on burrows below a certain size.
it does not allow for multiple castings of the same burrow over time.
the casting process takes more time than A. bellulus takes to construct a burrow.
the process of recovering the model distorts the resin's shape.
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "To better understand the burrowing habits of Alpheus bellulus (the tiger pistol shrimp), some studies have used resin casting to obtain precise measurements of the shrimps' burrows." |
|
| "Resin casting involves completely filling an empty burrow with a liquid plastic that hardens to create a three-dimensional model;" |
|
| "however, recovering the model inevitably requires destroying the burrow." |
|
| "In their 2022 study, Miyu Umehara and colleagues discovered that an x-ray computed tomography (CT) scanner can accurately record a burrow's measurements both at a moment in time and throughout the entire burrow-building process," |
|
Part B: Provide Passage Architecture
Main Point: While resin casting provides precise burrow measurements, a new CT scanning method offers the additional advantage of tracking burrow construction over time, something resin casting cannot accomplish.
Argument Flow: The passage starts by explaining the established resin casting method and its destructive limitation, then contrasts it with a newer CT scanning approach that can monitor burrow development continuously.
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 key insight is that resin casting requires destroying the burrow to recover the 3D model
- This creates a fundamental problem: once you've done the casting and retrieved your model, the burrow no longer exists
- You can't study the same burrow at different stages of construction because the first measurement destroys it
- CT scanning doesn't require destroying anything - it can take measurements repeatedly over time on the same burrow
- So the right answer should explain that resin casting prevents repeated measurements of the same burrow because the process is destructive
it can only be used on burrows below a certain size.
✗ Incorrect
- Claims resin casting only works on small burrows
- The passage never mentions size limitations and this doesn't explain why you can't track the building process over time
it does not allow for multiple castings of the same burrow over time.
✓ Correct
- Points out that you cannot do multiple castings of the same burrow over time
- This directly connects to our passage analysis: since recovering the model destroys the burrow, you can only cast once
- Perfectly explains why CT scanning can track the entire burrow-building process while resin casting cannot
the casting process takes more time than A. bellulus takes to construct a burrow.
✗ Incorrect
- Suggests casting takes longer than burrow construction
- The passage provides no timing information and even if true, this timing issue wouldn't prevent tracking development over time
the process of recovering the model distorts the resin's shape.
✗ Incorrect
- Claims the recovery process distorts the resin shape
- The passage states that resin casting provides precise measurements, contradicting any distortion
- Shape distortion wouldn't prevent multiple measurements over time anyway