PrepTest 109, Section 3, Question 10
The importance of the ozone layer to terrestrial(55 more words not shown)
Which one of the following(12 more words not shown)
- AAll wavelengths of(17 more words not shown)
- BFew species of(19 more words not shown)
- CSome species of(14 more words not shown)
- DA single wavelength(14 more words not shown)
- ESome wavelengths of(26 more words not shown)
Reading the argument
The ozone layer acts as a filter: some wavelengths get through, and others are blocked. If holes in that filter create an eye-damage risk, the natural connection is that harmful light can get through where it would otherwise be blocked.
That is the prediction I'd take into this most-strongly-supported question. Some wavelengths that can harm eyes are being filtered out, and holes make it easier for them to reach animals on the surface. We don't need a detailed theory of the atmosphere to follow that connection.
What we’re looking for
Keep the limits, though. The passage says severe eye damage is a danger for many species. It doesn't tell us exactly where all the holes are, how every species responds, or whether an intact ozone layer blocks every wavelength that could harm an eye. The answer should stay within what the filtering account supports.
Working the answers
- A
Blocking some harmful light doesn't mean blocking all harmful light. An intact ozone layer could provide important protection while still letting through other wavelengths capable of causing damage. The passage establishes the danger of losing some protection, not complete safety wherever the layer is intact.
- B
We aren't given this geographic information. The passage doesn't map the holes or tell us where most animal species live relative to them. Many species could face the stated danger without almost every species living in a threatened area. B adds a distribution the passage never supplies.
- C
Some species might escape all eye damage, but we aren't told that any do. Even if only certain species suffered severe damage, the others could suffer lesser damage. “Many could suffer severe damage” doesn't establish “some are immune to any damage.”
- D
This claims that one particular wavelength can severely damage the eyes of most species. The passage doesn't identify a single wavelength shared across that many species. Different wavelengths could pose problems for different animals.
Also, “many species” doesn't necessarily mean most species. D adds both a common harmful wavelength and a majority claim. A single wavelength means a particular kind of light here, not merely a tiny amount of light; the unsupported claim is about which wavelength harms which species.
- ECorrect
This makes the connection we predicted. Some eye-damaging wavelengths are more likely to reach the surface through holes than through the intact ozone layer. That explains why losing the layer's filtering protection could create the described risk.
The answer stays modest. It says some wavelengths are more likely to get through, not that all harmful light is normally blocked or that every animal will be injured.
More Must Be True questions
Learn the LSAT our way
Our platform drills Must Be True questions at your level and adjusts as you improve.