SAT Question d1539546: Answer & Explanation

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 ______

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Difficulty:Hard

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.

SAT Question d1539546: Inferences answer and explanation

Explanation

Why the other choices are wrong