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Zorluk: OrtaMust Be True / Most Strongly Supported

Agricultural researchers monitored test plots of drought-stressed legumes under varying soil and management conditions. In every plot where mycorrhizal fungal colonization exceeded 40 percent, root nodule nitrogen fixation remained stable throughout the dry season. However, no plot that received synthetic nitrogen fertilizer achieved mycorrhizal fungal colonization above 25 percent. In the southern test valley, all plots managed under the regenerative protocol maintained stable root nodule nitrogen fixation throughout the dry season, but several of these regenerative plots had received synthetic nitrogen fertilizer.

If the statements above are true, which one of the following must also be true?

  1. A
    Any legume plot in the southern test valley that maintained stable root nodule nitrogen fixation throughout the dry season must have achieved mycorrhizal fungal colonization above 40 percent.
  2. B
    No legume plot that achieves mycorrhizal fungal colonization above 40 percent can sustain root nodule nitrogen fixation if synthetic nitrogen fertilizer is subsequently applied.
  3. At least some legume plots with mycorrhizal fungal colonization of 25 percent or less maintained stable root nodule nitrogen fixation throughout the dry season.Cevap
  4. D
    Any legume plot that did not receive synthetic nitrogen fertilizer achieved mycorrhizal fungal colonization exceeding 40 percent.
  5. E
    Legume plots managed under the regenerative protocol produced higher total crop biomass than plots receiving synthetic nitrogen fertilizer.

Cevap

At least some legume plots with mycorrhizal fungal colonization of 25 percent or less maintained stable root nodule nitrogen fixation throughout the dry season.
The stimulus establishes that several regenerative plots in the southern valley received synthetic fertilizer. By the rule that no plot receiving synthetic fertilizer exceeds 25 percent colonization, these specific plots must have had colonization rates of 25 percent or less. Because all regenerative plots in that valley maintained stable nitrogen fixation throughout the dry season, these specific plots maintained stable fixation despite having colonization rates at or below 25 percent. Thus, it is logically guaranteed that at least some plots with colonization of 25 percent or less maintained stable nitrogen fixation.

Adım Adım Çözüm

1
Extract and formalize the factual premises from the stimulus
Premise 1: Fungal colonization > 40% guarantees stable nitrogen fixation. Premise 2: Synthetic fertilizer guarantees fungal colonization <= 25%. Premise 3: All southern valley regenerative plots had stable nitrogen fixation, and some of these plots received synthetic fertilizer.
Isolating the formal relationships prevents conflating sufficient conditions with necessary conditions.
2
Synthesize the premises regarding the subset of southern valley regenerative plots that received synthetic fertilizer
The regenerative plots that received synthetic fertilizer must have fungal colonization <= 25% (by Premise 2). At the same time, because they are regenerative plots in the southern valley, they maintained stable nitrogen fixation (by Premise 3).
Combining these specific constraints produces a deductively guaranteed overlap.
3
Derive the valid deductive inference
There exist plots (specifically, the fertilized southern valley regenerative plots) that had fungal colonization <= 25% while maintaining stable nitrogen fixation.
This matches the statement that at least some plots with colonization of 25% or less maintained stable nitrogen fixation.

Anahtar Kavram

Quantifier Intersection and Sufficient vs. Necessary Conditions
Tahmini Süre:1m 20s
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