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Difficulty: MediumInferences from the Text

In agronomy, the symbiotic relationship between certain cool-season grasses and endophytic fungi of the genus *Epichloë* has traditionally been characterized as strictly mutualistic. The endophytes produce alkaloids that deter insect and mammalian herbivores, while the host grasses supply essential nutrients and ensure fungal transmission via seed. However, recent field experiments reveal that under severe phosphorus limitation, the energetic cost of sustaining fungal metabolic pathways significantly outweighs any defensive benefit. In such nutrient-depleted soils, uninfected grass lineages demonstrate higher total biomass and seed production than their infected conspecifics. Furthermore, while alkaloid concentrations remain uniform across mature foliage, they drop sharply in root tissues, leaving infected grasses just as susceptible to subterranean nematodes as uninfected specimens.

Which of the following inferences about *Epichloë* endophyte infection in cool-season grasses is most strongly supported by the passage?

  1. A
    Grasses infected with *Epichloë* endophytes will invariably experience a net reduction in reproductive fitness when cultivated in phosphorus-deficient soils, regardless of the severity of aboveground herbivore pressure.
  2. B
    Soil phosphorus enrichment directly accelerates the transmission rate of *Epichloë* fungi from parent grasses to their seed progeny.
  3. The defensive advantages conferred by *Epichloë* endophyte infection do not extend uniformly across all anatomical structures of the host grass.Answer
  4. D
    Uninfected grass lineages synthesize alternative secondary metabolites that offer superior resistance against subterranean nematode infestation.
  5. E
    The mutualistic benefits of *Epichloë* endophytes are primarily responsible for the evolutionary dominance of cool-season grasses over warm-season grasses in temperate ecosystems.

Answer

The defensive advantages conferred by *Epichloë* endophyte infection do not extend uniformly across all anatomical structures of the host grass.
The correct response correctly synthesizes the contrast presented in the final sentence of the passage: because alkaloid concentrations remain present in mature foliage but drop sharply in root tissues, the defensive properties do not apply uniformly throughout the entire plant organism.

Step-by-Step Solution

1
Analyze the question stem and identify the task.
The task is to find an inference that is most strongly supported by the stated facts in the passage without extrapolating beyond the text.
LSAT inference questions require evaluating strictly entailed or strongly warranted conclusions based on explicit premises.
2
Evaluate textual evidence regarding the anatomical distribution of defensive benefits.
The final sentence states that alkaloid concentrations are uniform in mature foliage but drop sharply in root tissues, leaving the plant susceptible to subterranean nematodes.
Synthesizing the contrast between foliage (protected from herbivores) and roots (unprotected from nematodes) demonstrates that protection is localized rather than uniform throughout the plant.
3
Match the synthesized evidence to the answer choices while eliminating unsupported claims.
The statement expressing non-uniformity across anatomical structures accurately characterizes the foliage-versus-root contrast without exceeding the passage scope.
This inference avoids extreme qualifiers and remains tightly tethered to the passage text.

Key Concept

Textual Inference and Scope Calibration
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Topics

Inferences from the Text

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