Question

text 1
in separate studies, stephen meding and robert j. zasoski and xinhua he and colleagues examined whether plants transfer nutrients to one another using the common mycorrhizal network (cmn) - a lattice of fungal strands in the soil. meding and zasoski excluded all pathways other than the cmn by using barriers to keep the plants root systems separate while allowing mycorrhizal strands through - a crucial step he and colleagues study did not take.
text 2
meding and zasoski took the necessary precaution of separating the plants root systems (thereby excluding root - to - root transmission). however, any barrier used must allow the thread - like hyphae of a cmn to pass through, and this permeability would also allow liquids through. thus, the researchers experimental design cannot ensure that any nutrient transfer observed can be attributed to a cmn and not to some other pathway.
based on the texts, which choice best describes a point on which the author of text 1 and the author of text 2 would most likely agree?
a) meding and zasoskis study effectively excluded any explanation for nutrient transfer other than a cmn.
b) excluding root - to - root transfer of nutrients between plants is sufficient to ensure that any observed nutrient transfer must involve a cmn.
c) he and colleagues study was not designed in a way that would allow it to produce compelling evidence that nutrient transfer occurred via a cmn.
d) a barrier that is impervious to both roots and fungal strands is necessary to evaluate nutrient transfer via a cmn.

Explanation:

• Text 1 states that Meding and Zasoski excluded all pathways other than the CMN by using barriers to keep the plants' root systems separate while allowing mycorrhizal strands through, and that He and colleagues' study did not take this crucial step.
• Text 2 points out that the barriers used by Meding and Zasoski allow the thread - like hyphae of a CMN to pass through and also allow liquids through, so the experimental design cannot ensure that nutrient transfer is due to a CMN.
• Option C: Text 1 implies that He and colleagues' study is less rigorous (by not taking the “crucial step” of excluding root - to - root transfer properly). Text 2 focuses on the flaws in Meding and Zasoski's design but by implication (since He and colleagues' study is not as rigorous as Meding and Zasoski's in excluding root - to - root transfer, and Meding and Zasoski's has its own flaws), He and colleagues' study is not well - designed to show CMN - based nutrient transfer.
• Option A: Text 2 contradicts this as it shows Meding and Zasoski's design has flaws (liquids can pass through, so other pathways might exist).
• Option B: Text 2 shows that excluding root - to - root transfer is not sufficient (liquids can pass through the barrier, so other pathways for nutrient transfer might exist).
• Option D: Text 1 says Meding and Zasoski used a barrier that allowed fungal strands (mycorrhizal strands) through, so this option is incorrect.

Answer:

C. He and colleagues’ study was not designed in a way that would allow it to produce compelling evidence that nutrient transfer occurred via a CMN.