PrepTest 157, Section 3, Question 15
Ants sometimes live in hollow places in the(59 more words not shown)
Which one of the following,(16 more words not shown)
- AMicroscopic organisms that(16 more words not shown)
- BThe nutrients present(23 more words not shown)
- CThe ants that(20 more words not shown)
- DThe ants that(21 more words not shown)
- EMost plant species(18 more words not shown)
Reading the argument
Ants living in a plant's roots sound as though they might cause trouble. But these orchids are healthier when ants live in them. Why?
Maybe the ants help. The passage offers a possible mechanism: organic matter stored in the roots supplies additional nutrients. But there's another direction to consider. What if ants choose the healthiest orchids as their homes? Then the orchids' health could explain where the ants live, rather than the ants creating the better health.
What we’re looking for
We're asked for an alternative explanation. That selection idea is my first prediction: ants move into plants that are already doing well. It isn't the only possible answer. We need a different explanation of why orchids housing ants are healthier, so keep an open mind about a different benefit the ants might provide.
Working the answers
- A
Breaking down the stored organic matter could explain how the orchids obtain nutrients from it. That develops the explanation already offered; it doesn't give us a different explanation. An additional step in the same nutritional process isn't an alternative to that process.
- B
The same kinds of nutrients could still be helpful in an additional amount. Suppose the soil provides a nutrient and the material stored by ants supplies more of it. The original explanation could still work. In any case, B doesn't tell us what other factor explains why orchids with ants are healthier.
- CCorrect
The ants act as guards. Other insects eat the orchids' roots, and the ants eat those insects. With fewer root-eating pests, the orchids could stay healthier. That's a complete alternative route from having ants to better health.
It isn't the initial prediction that ants select already healthy plants. Instead, it gives the ants a different helpful role: protection rather than additional nutrition. We should accept that new route because it answers the question just as well as a supported version of our prediction would.
- D
Not helping with pollination doesn't explain the better health. If the ants did provide some useful pollinating service, that might offer a mechanism worth considering. Saying they don't play that role removes a possible explanation rather than supplying one.
- E
We need to explain the pattern in these orchids, not a general pattern across other plant species. Even if most plants harboring insects are more disease-prone, the orchids in the passage are healthier when ants live in them. E doesn't explain that particular result.
More Strengthen questions
Learn the LSAT our way
Our platform drills Strengthen questions at your level and adjusts as you improve.