Bunuel wrote:
Landfills, which store much of this country's garbage, still face significant lead-pollution risks. Discarded products such as old electronics are supposed to be tested for lead content. Objects with a high lead content are supposed to be treated as hazardous waste and discarded in locations other than landfills. However, one of the most common tests used to detect lead in discarded products frequently misses high lead concentrations.
Which of the following best describes the role of the bolded statement in the above passage?
A. It is the conclusion of an argument.
B. It is an objection to the argument's conclusion.
C. It is a statement that qualifies the evidence provided.
D. It is a fact in support of an argument.
E. It is an explanation that clarifies the argument's conclusion
OFFICIAL EXPLANATION:D.
The argument begins with an assertion that landfills continue to face a lead-pollution risk. The rest of the passage explains why: Certain refuse is supposed to be tested, and objects containing high lead counts are to be brought to special sites instead of landfills. But as the bolded sentence indicates, detection tests are not always accurate. This lends support to the initial assertion, which means that the first sentence is the argument's conclusion, while the fact in the final sentence is evidence for it. This rules out choice (A), which confuses the argument's main piece of evidence for its conclusion, and choice (B), which mistakenly asserts that the bolded supporting statement opposes the conclusion. Choice (C) is incorrect because the bolded statement represents the argument's main piece of evidence, not something that softens or tempers the other statements in the passage. As for choice (E), the bolded statement does not explain what the conclusion means; it tells us why it is so.