LR Drill Set 6, Question 12
Ancient civilizations often polluted their harbors with lead,(56 more words not shown)
The argument requires the assumption(1 more words not shown)
- Athe ancient civilizations(12 more words not shown)
- Bonly those ancient(13 more words not shown)
- Call technologically advanced(7 more words not shown)
- Dlead is the(8 more words not shown)
- Esediment layers beneath(8 more words not shown)
Reading the argument
We have evidence of lead pollution. How does that establish technological advancement?
The passage rules out a natural cause for these unusually high lead levels. Let's accept that. Ancient civilizations used lead in activities such as glassmaking and shipbuilding, so human activity provides a possible explanation for the accumulation.
I'd first wonder about the timing. Could lead enter the sediment after the activity that released it, so the layer doesn't identify exactly when the civilization used the harbor? The conclusion attaches its claim to the time the layer accumulated, and that connection deserves attention.
There's another question: how advanced must a civilization be to create this much pollution?
Perhaps a civilization could use lead and pollute a harbor without qualifying as technologically advanced. Nothing in the premises has yet tied those two descriptions together. The conclusion treats the high lead levels as a sign of a particular level of technology.
What we’re looking for
We're asked for an assumption the argument requires. We have more than one concern, so let's see which missing connection the choices address. A rule connecting this high level of pollution to technological advancement would help explain the central classification the author makes.
Working the answers
- A
The conclusion calls this civilization technologically advanced, not the most advanced. It doesn't rank civilizations by their technology or by how much lead they left. The most advanced civilization could leave less lead than another and the argument's particular classification could still be made. A adds a ranking the reasoning doesn't need.
- BCorrect
Only technologically advanced civilizations produced high levels of lead pollution in their harbors. That lets the author use the unusually high level as a sign of technological advancement. Without this restriction, a less advanced civilization could also have produced the evidence, undermining the move from pollution to an advanced harbor user. B addresses that missing link; it doesn't need to answer every separate question we raised about timing.
- C
This goes from technological advancement to some use of lead. We need to go from the high lead levels to technological advancement. Suppose every advanced civilization used lead, but many less advanced civilizations did too. C would be true, yet finding lead would still fail to distinguish the groups. It also says some use, which is different from high harbor pollution.
- D
The civilization could release mercury or other pollutants along with lead. Those additional substances wouldn't stop the author from using high lead levels as evidence. The argument doesn't require lead to be the only pollutant; it requires a connection between the particular evidence found and the proposed technological status.
- E
The passage rules out a natural explanation for levels this high, not for every trace of lead. Some naturally occurring lead could be present beneath harbors while unusually large quantities still indicated human activity. E needlessly turns a claim about an excessive amount into a claim that the natural amount must be zero.
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