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In preparation for a large-scale tree-planting project, Thomasville has recorded the location, species, and condition of every tree in its downtown area. The results will be compared with results of the last such tree census, taken 20 years ago. Planting trees primarily from the species that turns out to have the best record of survival will assure downtown Thomasville of an abundant tree population 20 years from now.
Which of the following, if true, most seriously undermines the claim that the tree planting proposal will assure an abundant tree population?
| Text from Passage | Analysis |
| In preparation for a large-scale tree-planting project, Thomasville has recorded the location, species, and condition of every tree in its downtown area. |
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| The results will be compared with results of the last such tree census, taken 20 years ago. |
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| Planting trees primarily from the species that turns out to have the best record of survival will assure downtown Thomasville of an abundant tree population 20 years from now. |
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The argument starts by describing Thomasville's thorough preparation - they did a complete tree survey. Then it explains their strategy - compare current results with 20-year-old data to find the best surviving species. Finally, it concludes that planting mostly these successful species will guarantee abundant trees in the future.
Planting trees primarily from the species with the best survival record will assure downtown Thomasville of an abundant tree population 20 years from now.
The evidence (comparing tree survival over 20 years) is supposed to support the conclusion (guaranteed future abundance), but this connection assumes that past survival patterns will perfectly predict future results and that no other factors matter.
Weaken - We need to find information that would reduce our belief in the conclusion that planting trees from species with the best survival record will assure an abundant tree population 20 years from now.
The key claim is very strong - it says the strategy will 'assure' an abundant tree population. This absolute certainty makes it vulnerable to scenarios showing the strategy might not guarantee success.
Look for scenarios that show why past survival success might not predict future abundance. We need to attack the logical connection between 'species that survived well in the past 20 years' and 'guaranteed abundant population in the next 20 years.' We can't question the facts that they did a census or that some species survived better than others, but we can question whether this guarantees future success.
This choice actually strengthens rather than weakens the argument. If environmental conditions won't become harsher, then the species that survived well in the past 20 years are even more likely to continue thriving. This supports the conclusion that planting these successful species will assure an abundant population, so it doesn't undermine the claim.
This information about record-keeping of cut-down trees doesn't impact the argument's logic. Whether we have good records of which trees were removed for construction doesn't affect whether planting species with good survival records will guarantee future abundance. This is essentially irrelevant information that doesn't weaken the conclusion.
The fact that some trees reached the natural end of their lifespan is expected and doesn't undermine the strategy. The argument is based on identifying species with the best survival records - if some trees died of old age, that's already factored into determining which species performed best overall. This doesn't challenge the logic of the planting strategy.
This choice discusses a general limitation of urban tree-growing but doesn't specifically attack the argument's conclusion. The argument already assumes they're working in urban conditions and comparing urban survival rates. Whether trees grow as well in cities as in nature doesn't matter for comparing which urban species performed best or whether planting the best performers will assure abundance.
This choice directly undermines the argument by revealing a critical flaw in the strategy. If Thomasville plants primarily one species (the one with the best survival record), they create dangerous vulnerability. A single disease outbreak could wipe out most of their trees, regardless of how well that species performed historically. This shows why concentrating on the 'best' species might not 'assure' an abundant population - it could actually guarantee disaster if a species-specific threat emerges.