It is currently 13 Dec 2017, 14:56

Decision(s) Day!:

CHAT Rooms | Ross R1 | Kellogg R1 | Darden R1 | Tepper R1


Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

The goblin fern, which requires

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Senior Manager
Senior Manager
avatar
D
Joined: 30 Jan 2016
Posts: 324

Kudos [?]: 239 [0], given: 97

Location: United States (MA)
Reviews Badge
The goblin fern, which requires [#permalink]

Show Tags

New post 02 Sep 2017, 08:41
7
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

39% (01:42) correct 61% (01:52) wrong based on 212 sessions

HideShow timer Statistics

The goblin fern, which requires a thick layer of leaf litter on the forest floor, is disappearing from North American forests. In spots where it has recently vanished, the leaf litter is unusually thin and, unlike those places where this fern still thrives, is teeming with the European earthworm Lumbricus rubellus, which eats leaf litter. L. rubellus is thus probably responsible for the fern's disappearance.

Which one of the following is an assumption on which the argument depends?

(A) Wherever there is a thick layer of leaf litter in North American forests, goblin ferns can be found.
(B) None of the eartbworms that are native to North America eat leaf litter.
(C) Dead leaves from goblin ferns make up the greater part of the layer of leaf litter on the forest floors where the goblin fem has recently vanished.
(D) There are no spots in the forests of North America where both goblin ferns and earthworms of the species L. rubellus can be found.
(E) L. rubellus does not favor habitats where the leaf litter layer is considerably thinner than what is required by goblin ferns.

Source: LSAT

Kudos! :-)
[Reveal] Spoiler: OA

_________________

+1 Kudos is the best way to say "Thank you!"

Kudos [?]: 239 [0], given: 97

Director
Director
User avatar
P
Joined: 28 Mar 2017
Posts: 690

Kudos [?]: 166 [0], given: 138

Re: The goblin fern, which requires [#permalink]

Show Tags

New post 02 Sep 2017, 11:38
The goblin fern, which requires a thick layer of leaf litter on the forest floor, is disappearing from North American forests. In spots where it has recently vanished, the leaf litter is unusually thin and, unlike those places where this fern still thrives, is teeming with the European earthworm Lumbricus rubellus, which eats leaf litter. L. rubellus is thus probably responsible for the fern's disappearance.

Which one of the following is an assumption on which the argument depends?

(A) Wherever there is a thick layer of leaf litter in North American forests, goblin ferns can be found. -We already know this information from the passage. It can't be an assumption.
(B) None of the eartbworms that are native to North America eat leaf litter. -We are worried about the L. Rubellus earthworms. Out of scope.
(C) Dead leaves from goblin ferns make up the greater part of the layer of leaf litter on the forest floors where the goblin fem has recently vanished. -We are not worried about what constitute the various parts of leaf litter.
(D) There are no spots in the forests of North America where both goblin ferns and earthworms of the species L. rubellus can be found. -This will be a weakener.
(E) L. rubellus does not favor habitats where the leaf litter layer is considerably thinner than what is required by goblin ferns. -Correct. The L. Rubellus are found in thick covers of leaf litter that are essential for the growth of goblin fern.
_________________

Kudos if my post helps!

Helpful links:
1. e-GMAT's ALL SC Compilation
2. LSAT RC compilation
3. Actual LSAT CR collection by Broal
4. QOTD RC (Carcass)
5. Challange OG RC

Kudos [?]: 166 [0], given: 138

Intern
Intern
avatar
B
Joined: 26 Mar 2016
Posts: 22

Kudos [?]: 2 [0], given: 3

The goblin fern, which requires [#permalink]

Show Tags

New post 02 Sep 2017, 11:48
OA -> E
Opposite is not true i.e L rubellus is not there because leaf layer is already thin.

Kudos [?]: 2 [0], given: 3

Director
Director
User avatar
P
Joined: 28 Mar 2017
Posts: 690

Kudos [?]: 166 [0], given: 138

Re: The goblin fern, which requires [#permalink]

Show Tags

New post 02 Sep 2017, 11:59
shalabhg27 wrote:
OA -> E
Opposite is not true i.e L rubellus is not there because leaf layer is already thin.


Hi,

(E) L. rubellus does not favor habitats where the leaf litter layer is considerably thinner than what is required by goblin ferns.
Negation: "L. rubellus does not favor habitats where the leaf litter layer is NOT considerably thinner than what is required by goblin ferns".

This means that wherever the litter is thick (not considerably thin), they are not present. --> If they are not present in the thick layer of litter, then this weakens the argument, since it would mean that the thick layer of litter is being thinned out by some other being/natural force than the L. Rubellus.

OA is correct.
Hope that helps !!

P.S.: 1 piece of advice for you; instead of arguing that why the OA is incorrect, try to understand where did you go wrong. Since, this is an official LSAT question, it can't be wrong. It will help you to gain more knowledge.
_________________

Kudos if my post helps!

Helpful links:
1. e-GMAT's ALL SC Compilation
2. LSAT RC compilation
3. Actual LSAT CR collection by Broal
4. QOTD RC (Carcass)
5. Challange OG RC

Kudos [?]: 166 [0], given: 138

Senior Manager
Senior Manager
avatar
D
Joined: 30 Jan 2016
Posts: 324

Kudos [?]: 239 [0], given: 97

Location: United States (MA)
Reviews Badge
Re: The goblin fern, which requires [#permalink]

Show Tags

New post 14 Sep 2017, 23:27
Quote:
The trigger "˜thus’ helps us locate the conclusion here: L. rubellus is probably responsible for the fern’s disappearance. This is a causation conclusion: L is causing the fern to disappear. What is this conclusion based on? areas where fern recently vanished are teeming with L and have unusually thin leaf litter (and we’re told L eats leaf litter). It certainly seems reasonable to conclude that this is all L’s fault, but we know we must be very careful when making a causation conclusion. The premises offer us a correlation, but that’s never enough to prove causation. Perhaps an unknown factor is causing the fern to vanish, and L didn’t enter those areas until later? This could all just be one big misunderstanding! Let’s diagram the core:

Spots where fern recently vanished have unusually thin leaf litter, which is required by the fern + those spots are teeming with L, which eats leaf litter --> L is probably responsible for the fern’s disappearance

We’re looking for an answer choice that will make a coincidence less likely, and we’ll get rid of answer choices if negating them doesn’t kill the conclusion:

(A) doesn’t mention L so probably wrong; let’s negate it and see what happens: some North American forests with thick leaf litter don’t have any fern. No one ever said fern has to be in every spot that has thick leaf litter! So, even if the opposite of (A) is true, L could still be the reason for the fern’s disappearance. Get rid of this one.

(B) Let’s negate this one too: some earthworms other than L eat leaf litter. Even so, L could still be responsible for the fern’s disappearance. Get rid of this one.

(C) You’d probably expect to find evidence of dead fern in areas where the fern recently vanished. What if the fern’s dead leaves only made up the smaller part of the leaf litter (again, negation)? This changes nothing... L could still be responsible for the fern’s disappearance. Get rid of this one.

(D) Try negation again: what if you could find some spots in North American forests that have both L and fern? Even then, L could still be responsible for the fern’s disappearance _ perhaps the fern will disappear from those spots as well in the near future. Get rid of this one.

(E) Negation has worked really well for us in the first four answer choices, and at this point we’re hoping (E) is right, otherwise we’re in trouble. Let’s try negating this one as well: L favors habitats where the leaf litter layer is considerably thinner than what is required by the fern. Aha! This means that the fern vanished before L arrived! L couldn’t be responsible for the fern’s disappearance!

So (E) is correct.

_________________

+1 Kudos is the best way to say "Thank you!"

Kudos [?]: 239 [0], given: 97

Re: The goblin fern, which requires   [#permalink] 14 Sep 2017, 23:27
Display posts from previous: Sort by

The goblin fern, which requires

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.