A government agency released results showing that the average lead

OFFICIAL EXPLANATION:

Identify the Question Type:

The words “contributes most to an explanation” indicate that this is an Explain question. Expect there to be a paradox or apparent contradiction in the stimulus, and the answer to explain how both parts of the apparent contradiction can be true at the same time.

Untangle the Stimulus:

Untangle the stimulus in an Explain question by paraphrasing the two parts of the apparent contradiction. The two are often separated by a contrast word, such as “but,”“yet,” or, in this case, “however.” On the one hand, domestically produced wines tested in the bottle often had lead contents lower than the amount allowed for drinking water. On the other hand, when the wines were poured, they (along with imported wines) had lead levels higher than the standard for drinking water.

Predict the Answer:

As with most Explain questions, it’s difficult to predict an exact answer here. There are many possible reasons for the surprise difference in test results. However, it is important to note that the lead levels were lower in the bottle, and only high after the wine was poured. Expect the correct answer to show how lead levels would increase during the pouring process.

Evaluate the Choices:

(D) provides a perfectly reasonable explanation for both results, and is the answer. Lead from foil caps may collect on the lips of bottles, so that the wine inside the bottle is low in lead, but then the wine picks up lead as it passes the bottle lip.

(A) explains why there might be lead present in wine, but not why the lead level would increase when the wine is poured from the bottle.

(B) at most explains why there might be lead present in wine, but not why the lead level would increase when the wine is poured from the bottle.

(C) explains how lead deposits might build up inside the bottle, but once the bottle is opened, the leaky cork no longer matters. This fails to explain why the lead level would be higher when the wine is poured.

(E) doesn't say what kind of contamination is present in the groundwater. Still, at most this might explain high lead levels in domestic wine, but not the reason for the lead increase when wine is poured.

TAKEAWAY: The answer to an Explain question must show how both parts of the apparent contradiction can be true at the same time. Watch out for choices that deal with only one part of the contradiction.