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Difficulty: MediumPassage Assumptions and Underlying Premises

Read the following passage carefully:

'To curb rising urban air pollution and reduce fossil fuel import dependencies, state transport corporations in several tier-2 cities have initiated ambitious programs to replace conventional diesel buses with electric buses (e-buses). Proponents argue that subsidizing up to 40% of the upfront purchase cost of e-buses will enable municipal transit authorities to achieve complete fleet electrification within five years, while significantly lowering operational emissions. However, regional power distribution companies in these cities currently rely primarily on coal-fired thermal power plants and experience frequent voltage fluctuations and grid overloads during peak demand hours. Critics point out that without concurrent grid modernization and dedicated high-capacity charging infrastructure powered by renewable energy, the rapid introduction of e-bus fleets may shift emissions upstream to thermal power plants rather than reducing net regional pollution, while increasing the risk of local grid instability.'

Based on the passage above, evaluate whether the following statement functions as an essential underlying premise of the critics' argument:

The net environmental benefit of transitioning from diesel buses to electric buses is directly contingent on the carbon intensity of the source electricity used to charge the vehicle fleet.

Answer: Answer

Answer

The statement accurately identifies an essential underlying premise of the critics' argument in the passage.
The statement is correct (True) because the critics' concern about upstream emissions relies on the logical bridge that electric vehicles are only as clean as the power grid supplying them. If grid carbon intensity did not matter, their conclusion that coal-powered e-buses fail to reduce net pollution would break down.

Step-by-Step Solution

1
Identify the main conclusion of the critics' argument in the passage.
The critics argue that without renewable charging infrastructure, deploying e-buses may merely shift emissions upstream to coal plants rather than lowering net regional pollution.
Isolating the specific claim is necessary to determine what implicit assumptions support it.
2
Analyze the implicit link between the premise statement and the critics' conclusion.
The critics connect the use of coal-fired thermal power to a failure in achieving net pollution reduction.
An assumption bridges explicit evidence (coal grid power) to the author's/critics' conclusion (no net environmental gain).
3
Apply the Negation Test to verify necessity.
Negating the statement gives: 'The net environmental benefit of electric buses is NOT contingent on the carbon intensity of the source electricity.' If this negation were true, charging e-buses via coal power would still yield net environmental benefits, completely undermining the critics' warning.
If the negated assumption destroys the validity of the argument, the original statement is a necessary underlying premise.

Key Concept

Identifying Implicit Premises and Applying the Negation Test
Estimated Time:1m 30s
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Topics

Passage Assumptions and Underlying Premises

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