Tides can deposit large quantities of dead vegetation within a salt marsh, smothering healthy plants and leaving a salt panne—a...

GMAT Information and Ideas : (Ideas) Questions

Source: Official

Information and Ideas

Inferences

HARD

...

Notes

Post a Query

Tides can deposit large quantities of dead vegetation within a salt marsh, smothering healthy plants and leaving a salt panne—a depression devoid of plants that tends to trap standing water—in the marsh's interior. Ecologist Kathryn Beheshti and colleagues found that burrowing crabs living within these pannes improve drainage by loosening the soil, leading the pannes to shrink as marsh plants move back in. At salt marsh edges, however, crab-induced soil loosening can promote marsh loss by accelerating erosion, suggesting that the burrowing action of crabs ______

Which choice most logically completes the text?

can be beneficial to marshes with small pannes but can be harmful to marshes with large pannes.

may promote increases in marsh plants or decreases in marsh plants, depending on the crabs' location.

tends to be more heavily concentrated in areas of marsh interiors with standing water than at marsh edges.

varies in intensity depending on the size of the panne relative to the size of the surrounding marsh.

Solution

Step 1: Decode and Map the Passage

Part A: Passage Analysis Table

Text from Passage	Analysis
Tides can deposit large quantities of dead vegetation within a salt marsh, smothering healthy plants	What it says: Tides bring dead plants that kill healthy plants What it does: Introduces a problem in salt marshes What it is: Context/problem setup
and leaving a salt panne—a depression devoid of plants that tends to trap standing water—in the marsh's interior.	What it says: Result = salt panne (plant-free depression with trapped water) What it does: Explains what the dead vegetation creates What it is: Definition/consequence
Ecologist Kathryn Beheshti and colleagues found that burrowing crabs living within these pannes improve drainage by loosening the soil,	What it says: Study: crabs in pannes loosen soil and improve drainage What it does: Presents research finding about crab effects in pannes What it is: Research evidence
leading the pannes to shrink as marsh plants move back in.	What it says: Result: pannes shrink, plants return What it does: Explains the positive outcome of crab activity in pannes What it is: Beneficial consequence
At salt marsh edges, however, crab-induced soil loosening can promote marsh loss by accelerating erosion,	What it says: BUT at edges: crab loosening causes faster erosion and marsh loss What it does: Contrasts with the previous positive effect by showing negative effects at edges What it is: Contrasting evidence
suggesting that the burrowing action of crabs ______	What it says: [COMPLETION NEEDED] What it does: Sets up conclusion about crab burrowing effects What it is: Conclusion requiring completion

Part B: Passage Architecture & Core Elements

Main Point: Crab burrowing has opposite effects depending on where it occurs—beneficial in marsh interiors but harmful at marsh edges.

Argument Flow: The passage starts with a salt marsh problem (dead vegetation creating pannes), then presents research showing crabs can help solve this problem by improving drainage in pannes. However, it contrasts this with the finding that the same crab activity causes harm at marsh edges through increased erosion, leading to a conclusion about the location-dependent nature of crab effects.

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 research shows crab burrowing has two completely different outcomes:
- In salt pannes (marsh interior): positive effect (helps plants return)
- At marsh edges: negative effect (increases erosion and marsh loss)
The key insight is that the SAME activity (crab burrowing) produces opposite results depending on WHERE it happens
The right answer should capture this location-dependent nature of the effects—that crab burrowing can be either beneficial or harmful depending on where the crabs are located within the marsh system

Answer Choices Explained

can be beneficial to marshes with small pannes but can be harmful to marshes with large pannes.

✗ Incorrect

Focuses on panne size (small vs. large pannes)
The passage doesn't discuss panne size as a factor
Misses the key point about location (interior vs. edges)

may promote increases in marsh plants or decreases in marsh plants, depending on the crabs' location.

✓ Correct

Directly captures the location-dependent effects: depending on the crabs' location
Accurately reflects both outcomes: increases in marsh plants (interior) and decreases in marsh plants (edges)
Matches our prethinking about the same activity having opposite effects based on where it occurs

tends to be more heavily concentrated in areas of marsh interiors with standing water than at marsh edges.

✗ Incorrect

Focuses on concentration/intensity of burrowing activity
The passage doesn't compare how heavily concentrated crab burrowing is in different areas
This trap choice might seem appealing because the passage mentions both interior and edge locations, but it's discussing distribution rather than effects

varies in intensity depending on the size of the panne relative to the size of the surrounding marsh.

✗ Incorrect

Discusses intensity varying by size ratios
The passage doesn't mention anything about panne size relative to marsh size
Completely misses the location-based effects that drive the passage's logic

Rate this Solution

Tell us what you think about this solution

...

Forum Discussions

Start a new discussion

Post

Previous Attempts

Loading attempts...