PrepTest 109, Section 2, Question 21
Experts anticipate that global atmospheric concentrations of carbon(445 more words not shown)
Which one of the following,(17 more words not shown)
- AThe roots of(32 more words not shown)
- BWhen grown in(22 more words not shown)
- CWhen trees of(33 more words not shown)
- DWhen two different(31 more words not shown)
- EThe number of(26 more words not shown)
Reading the passage
The hypothesis is that plants with high photosynthetic efficiency may lose their edge when CO2 rises. For the LEAST consistent result, I'd look for a high-efficiency plant still outperforming a lower-efficiency competitor under the new conditions.
What we’re looking for
The plants needn't be corn and sugarcane. Another pair could test the same relationship. We need to match the efficiencies and the direction of the result.
Working the answers
- A
High-efficiency grasses lose territory to trees. That fits a weakening of their former advantage. We aren't told the trees' efficiency, but this doesn't show the efficient grasses continuing to dominate.
- B
Low-efficiency weeds thrive where crops previously dominated. That's just the sort of problem paragraph 2 describes.
- CCorrect
The high-efficiency trees grow faster than the low-efficiency grasses even in the CO2-rich atmosphere. Their edge remains visible. This is the opposite direction from the expected loss of an advantage, making it the least consistent result here. It doesn't prove no efficient crop could ever lose ground; the hypothesis says “may lose that edge,” and we're choosing the example that fits least well.
- D
These grasses have equal photosynthetic efficiency. One outgrowing the other doesn't test whether a high-efficiency plant loses its advantage over a low-efficiency plant.
- E
A decline in legumes and soil fertility doesn't provide the needed efficiency comparison. The problem isn't that legumes are new: trees are new in C too. This result simply doesn't show a high-efficiency species retaining its advantage over a lower-efficiency one.
More Application questions
Learn the LSAT our way
Our platform drills Application questions at your level and adjusts as you improve.