PrepTest 142

Incorrect. This answer calls a premise into question while also failing to establish that any large trees sold at Three Rivers are on this acceptable list—two reasons to eliminate it.

Incorrect. First, this answer doesn't establish that the cottonwoods were among the trees the group purchased. Second, if anything, this answer hurts the argument.

Incorrect. This is more or less the same statement as a premise, so it doesn't strengthen the argument.

Incorrect. This answer seems to contradict the master plan, but their rarity is out of scope anyway, so this answer is incorrect.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen

Stimulus Summary:
Master plan Ð Plant local trees that don't get too big.
Donated trees Ð Purchased at Three Rivers Nursery (mostly native trees/shrubs)
Conclusion Ð These trees probably fit the master plan

Answer Anticipation:
The master plan calls for two things from the trees—that they're native to the area, and that they're not too big. The donated trees are established to be mostly from the area (matching the conclusion's "probably"), but it doesn't establish anything about their size. Presumably the shrubs won't grow to be very large, but there's no indication that the trees won't. To strengthen the argument, then, we should establish that the trees sold at Three Rivers aren't very large.

Answer Explanation:
This answer directly establishes that the trees at Three Rivers Nursery meet the second criteria set out in the master plan, thus strengthening the conclusion.

Key Takeaway:
When criteria are established, make sure you note them so you don't lose track as the argument progresses. It's not unheard of for an argument on the LSAT to "forget" about an earlier statement!