GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 19 Jun 2018, 12:42

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

Oceanologist: Recently an unprecedented number of dead dolphins washed

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

Hide Tags

1 KUDOS received
Retired Moderator
User avatar
Joined: 06 Jul 2014
Posts: 1259
Location: Ukraine
Concentration: Entrepreneurship, Technology
GMAT 1: 660 Q48 V33
GMAT 2: 740 Q50 V40
GMAT ToolKit User Premium Member
Oceanologist: Recently an unprecedented number of dead dolphins washed [#permalink]

Show Tags

New post 13 Sep 2015, 10:10
1
5
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

61% (01:57) correct 39% (02:22) wrong based on 267 sessions

HideShow timer Statistics

Oceanologist: Recently an unprecedented number of dead dolphins washed ashore along the mid-Atlantic coast. In the blood of over half of the dolphins, marine biologists discovered a brevotoxin that had been emitted by the alga Ptychodiscus brevis, in what is known as a red tide. Additionally, polychlorinated biphenyls (PCB), a toxic industrial compound, was also found in the dolphin’s blood. A reasonable conclusion, and indeed one many have drawn, is that the dolphins were simply victims of the brevotoxin. Nonetheless, brevotoxins, by themselves, are not lethal to dolphins, though they do tax the dolphins system. Furthermore, most dolphins have some accumulated brevotoxins in their blood without suffering any ill health effects. Therefore, the brevotoxins alone cannot explain the mass beaching of dead dolphins.

Which of the following, if true, does most to help explain the oceanologist’s doubt that the brevotoxins were the primary cause of the dolphins washing upon shore?

A) Most stricken dolphins that wash upon shore, whether or not they eventually die, tend to do so in the Gulf of Mexico.
B) Shortly before the dolphins washed ashore, a major oil spill not only caused algae to release brevotoxins but also released an array of deleterious industrial pollutants, including PCB.
C) While PCB can cause metabolic imbalances in dolphins so that they stop eating prematurely, the dose of PCB a dolphin encounters in the wild is unlikely to pose a lethal threat to a dolphin.
D) Scientists, near to the site of the beached dolphins, discovered a group of beach sea otters exhibiting similar symptoms as the dolphins.
E) PCB and brevotoxins exercise different effects on an organism, with PCB causing visible lesions.

_________________

Simple way to always control time during the quant part.
How to solve main idea questions without full understanding of RC.
660 (Q48, V33) - unpleasant surprise
740 (Q50, V40, IR3) - anti-debrief ;)

Manager
Manager
avatar
Joined: 21 Mar 2014
Posts: 58
Location: India
Concentration: Strategy, Technology
GMAT ToolKit User
Re: Oceanologist: Recently an unprecedented number of dead dolphins washed [#permalink]

Show Tags

New post 13 Sep 2015, 10:48
though I don't disagree with option B, but option C makes more sense since, it completely eliminates the possibility PCB is responsible for dolphins being washed ashore..The question stem asks us to select an option that explains why brevotoxins were the primary cause of the dolphins washing upon shore, and C precisely does that by stating PCB is not lethal. Option B on the other hand includes additional industrial wastes; so it's not perfectly clear whether brevotoxins were lethal or the industrial pollutants..
Intern
Intern
avatar
Joined: 01 Jan 2015
Posts: 15
Location: India
Concentration: Technology, Marketing
WE: Information Technology (Computer Software)
Re: Oceanologist: Recently an unprecedented number of dead dolphins washed [#permalink]

Show Tags

New post 13 Sep 2015, 14:54
Hi Harley1980,
Can you please explain what is the problem with answer choice C ?
Thanks in advance.
Intern
Intern
avatar
Joined: 26 Sep 2014
Posts: 2
Location: India
WE: General Management (Manufacturing)
Oceanologist: Recently an unprecedented number of dead dolphins washed [#permalink]

Show Tags

New post 13 Sep 2015, 18:06
raj44 wrote:
though I don't disagree with option B, but option C makes more sense since, it completely eliminates the possibility PCB is responsible for dolphins being washed ashore..The question stem asks us to select an option that explains why brevotoxins were the primary cause of the dolphins washing upon shore, and C precisely does that by stating PCB is not lethal. Option B on the other hand includes additional industrial wastes; so it's not perfectly clear whether brevotoxins were lethal or the industrial pollutants..


"X --> Y" but oceanologists are saying that "X didn't cause Y".

If X didn't cause Y, then what caused Y ? There must be "Z" which led to Y.

Z-->Y

Option B exactly covers that.
2 KUDOS received
Retired Moderator
User avatar
Joined: 06 Jul 2014
Posts: 1259
Location: Ukraine
Concentration: Entrepreneurship, Technology
GMAT 1: 660 Q48 V33
GMAT 2: 740 Q50 V40
GMAT ToolKit User Premium Member
Re: Oceanologist: Recently an unprecedented number of dead dolphins washed [#permalink]

Show Tags

New post 13 Sep 2015, 23:47
2
subhamoycomputer wrote:
Hi Harley1980,
Can you please explain what is the problem with answer choice C ?
Thanks in advance.


Hello subhamoycomputer

Option C is a weakener because it says that PCB is ok and dolphin have it in the blood naturally. So it is possible that scientists found minimal dose of PCB that can not kill all these doplhines.

And B gives us another reason why dolphin are dead: PCB from oil spill. Answer does not says it directly but in strengthen/weaken question we need only possibility so it is ok.
_________________

Simple way to always control time during the quant part.
How to solve main idea questions without full understanding of RC.
660 (Q48, V33) - unpleasant surprise
740 (Q50, V40, IR3) - anti-debrief ;)

2 KUDOS received
Retired Moderator
User avatar
Joined: 06 Jul 2014
Posts: 1259
Location: Ukraine
Concentration: Entrepreneurship, Technology
GMAT 1: 660 Q48 V33
GMAT 2: 740 Q50 V40
GMAT ToolKit User Premium Member
Re: Oceanologist: Recently an unprecedented number of dead dolphins washed [#permalink]

Show Tags

New post 13 Sep 2015, 23:51
2
1
raj44 wrote:
though I don't disagree with option B, but option C makes more sense since, it completely eliminates the possibility PCB is responsible for dolphins being washed ashore..The question stem asks us to select an option that explains why brevotoxins were the primary cause of the dolphins washing upon shore, and C precisely does that by stating PCB is not lethal. Option B on the other hand includes additional industrial wastes; so it's not perfectly clear whether brevotoxins were lethal or the industrial pollutants..


Hello raj44

"The question stem asks us to select an option that explains why brevotoxins were the primary cause of the dolphins washing upon shore"

Here is wrinkle in the question:
The question asks us to "explain the oceanologist’s doubt that the brevotoxins were the primary cause of the dolphins washing upon shore"

We need to explain why brevotoxin is not the primary cause.

GMAT really likes such wrinkles and sometimes one word completely change the question so we need to read very carefully.
_________________

Simple way to always control time during the quant part.
How to solve main idea questions without full understanding of RC.
660 (Q48, V33) - unpleasant surprise
740 (Q50, V40, IR3) - anti-debrief ;)

Retired Moderator
User avatar
S
Joined: 18 Sep 2014
Posts: 1174
Location: India
GMAT ToolKit User Premium Member Reviews Badge
Re: Oceanologist: Recently an unprecedented number of dead dolphins washed [#permalink]

Show Tags

New post 14 Sep 2015, 02:22
Oceanologist: Recently an unprecedented number of dead dolphins washed ashore along the mid-Atlantic coast. In the dolphins blood discovered a brevotoxin and polychlorinated biphenyls (PCB), a toxic industrial compound.

A reasonable conclusion is that the dolphins were simply victims of the brevotoxin.

But, brevotoxins, by themselves, are not lethal to dolphins.

addnal info: Most dolphins have some accumulated brevotoxins in their blood without suffering any ill health effects.

Conclusion: Therefore, the brevotoxins alone cannot explain the mass beaching of dead dolphins.

Which of the following explains the oceanologist’s doubt that the brevotoxins were the primary cause of the dolphins death?

A) Most stricken dolphins that wash upon shore tend to die in the Gulf of Mexico.(OFS)
B) Shortly before the dolphins washed ashore, a major oil spill not only caused algae to release brevotoxins but also released an array of deleterious industrial pollutants, including PCB.(This attacks the assumption behind the causal argument and explains the reason)
C) While PCB can cause metabolic imbalances in dolphins so that they stop eating prematurely, the dose of PCB a dolphin encounters in the wild is unlikely to pose a lethal threat to a dolphin.(This explains that PCB cannot result in dolphins death but does nothing to support that brevotoxins are not the reason for dolphins death)
D) Scientists, near to the site of the beached dolphins, discovered a group of beach sea otters exhibiting similar symptoms as the dolphins.(OFS this is regarding otters now)
E) PCB and brevotoxins exercise different effects on an organism, with PCB causing visible lesions.(Does not help in anyway)
_________________

The only time you can lose is when you give up. Try hard and you will suceed.
Thanks = Kudos. Kudos are appreciated

http://gmatclub.com/forum/rules-for-posting-in-verbal-gmat-forum-134642.html
When you post a question Pls. Provide its source & TAG your questions
Avoid posting from unreliable sources.


My posts
http://gmatclub.com/forum/beauty-of-coordinate-geometry-213760.html#p1649924
http://gmatclub.com/forum/calling-all-march-april-gmat-takers-who-want-to-cross-213154.html
http://gmatclub.com/forum/possessive-pronouns-200496.html
http://gmatclub.com/forum/double-negatives-206717.html
http://gmatclub.com/forum/the-greatest-integer-function-223595.html#p1721773
https://gmatclub.com/forum/improve-reading-habit-233410.html#p1802265

SVP
SVP
avatar
P
Joined: 12 Dec 2016
Posts: 1899
Location: United States
GMAT 1: 700 Q49 V33
GPA: 3.64
GMAT ToolKit User Premium Member
Oceanologist: Recently an unprecedented number of dead dolphins washed [#permalink]

Show Tags

New post 11 Jan 2018, 21:59
the pattern in B looks like a pattern in a weaken question. Nevertheless, since this question is neither strengthen nor weaken, and since the question stem is "doubt that the brevotoxins were the primary cause of the dolphins washing upon shore?" => nothing is wrong with B

Let's take another look at the question wording:

Which of the following, if true, does most to help explain the oceanologist’s doubt that the brevotoxins were the primary cause of the dolphins washing upon shore?
We can rephrase this to say:

Which of the following, if true, does most to help explain why the oceanologist does not think that the brevotoxins were the primary cause of the dolphins washing upon shore?

Well, if the oceanologist does not think that the brevotoxins were the primary cause of the dolphins washing upon shore, then the oceanologist must think that there is another cause that was the primary cause. Therefore, we need to find what the primary cause could be.

First, remember to choose an answer choice that supports the biologist's conclusion that the dolphins died NOT just from brevotoxin; some people out there do think that it was this toxin, but the oceanologist thinks it must have been something else.
Oceanologist: Recently an unprecedented number of dead dolphins washed   [#permalink] 11 Jan 2018, 21:59
Display posts from previous: Sort by

Oceanologist: Recently an unprecedented number of dead dolphins washed

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


cron

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.