Find all School-related info fast with the new School-Specific MBA Forum

It is currently 22 Oct 2014, 06:39

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

When there is less rainfall than normal, the water level of

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Senior Manager
Senior Manager
avatar
Joined: 07 Sep 2010
Posts: 340
Followers: 3

Kudos [?]: 156 [0], given: 136

When there is less rainfall than normal, the water level of [#permalink] New post 02 Jul 2012, 07:14
2
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

71% (02:20) correct 29% (01:30) wrong based on 446 sessions
When there is less rainfall than normal, the water level of Australian rivers falls and the rivers flow more slowly. Because algae whose habitat is river water grow best in slow-moving water, the amount of algae per unit of water generally increases when there has been little rain. By contrast, however, following a period of extreme drought, algae levels are low even in very slow-moving river water.

Which of the following, if true, does most to explain the contrast described above?

(A) During periods of extreme drought, the populations of some of the species that feed on algae tend to fall.
(B) The more slowly water moves, the more conducive its temperature is to the growth of algae.
(C) When algae populations reach very high levels, conditions within the river can become toxic for some of the other species that normally live there.
(D) Australian rivers dry up completely for short intervals in periods of extreme drought.
(E) Except during periods of extreme drought, algae levels tend to be higher in rivers in which the flow has been controlled by damming than in rivers that flow freely.

[Reveal] Spoiler:
Request you to please provide an explanation of A vs D.
Thanks
H
[Reveal] Spoiler: OA

_________________

+1 Kudos me, Help me unlocking GMAT Club Tests

Director
Director
User avatar
Status: Final Countdown
Joined: 17 Mar 2010
Posts: 564
Location: India
GPA: 3.82
WE: Account Management (Retail Banking)
Followers: 13

Kudos [?]: 144 [0], given: 75

Re: When there is less rainfall than normal [#permalink] New post 02 Jul 2012, 07:29
Less rainfall ---> slow movement of water ----> more algae
After the drought --->less water/flow----------->less algae

Answer must explain that even if the drought bring low water ,the growth of algae drops.

We need to prove that the growth of algae depends on other factors also OR the reason decremented algae is something else? OR there is no water at all for the growth of algae.

(D) says it clearly that "... rivers dry up completely for short intervals in periods of extreme drought.

Means-No water /or very less in a after-drought condition.
_________________

" Make more efforts "
Press Kudos if you liked my post

2 KUDOS received
Manager
Manager
avatar
Joined: 19 Oct 2011
Posts: 134
Location: India
Followers: 2

Kudos [?]: 177 [2] , given: 33

Re: When there is less rainfall than normal [#permalink] New post 02 Jul 2012, 08:09
2
This post received
KUDOS
(A) During periods of extreme drought, the populations of some of the species that feed on algae tend to fall.
if the populations of species that feed on algae tend to fall ---> less feeding on algae --> algae population will increase.

We want to resolve the paradox ( :idea: we want to find a reason why algae population goes down during extreme drought).
D is a clear winner in this case. :!:
_________________

Encourage me by pressing the KUDOS if you find my post to be helpful.



Help me win "The One Thing You Wish You Knew - GMAT Club Contest"
the-one-thing-you-wish-you-knew-gmat-club-contest-140358.html#p1130989

Expert Post
2 KUDOS received
Veritas Prep GMAT Instructor
User avatar
Joined: 16 Oct 2010
Posts: 4876
Location: Pune, India
Followers: 1152

Kudos [?]: 5359 [2] , given: 165

Re: When there is less rainfall than normal, the water level of [#permalink] New post 03 Jul 2012, 20:06
2
This post received
KUDOS
Expert's post
imhimanshu wrote:
When there is less rainfall than normal, the water level of Australian rivers falls and the rivers fl ow more slowly.
Because algae whose habitat is river water grow best in slow-moving water, the amount of algae per unit of
water generally increases when there has been little rain. By contrast, however, following a period of extreme
drought, algae levels are low even in very slow-moving river water.
Which of the following, if true, does most to explain the contrast described above?
(A) During periods of extreme drought, the populations of some of the species that feed on algae tend to fall.
(B) The more slowly water moves, the more conducive its temperature is to the growth of algae.
(C) When algae populations reach very high levels, conditions within the river can become toxic for some of
the other species that normally live there.
(D) Australian rivers dry up completely for short intervals in periods of extreme drought.
(E) Except during periods of extreme drought, algae levels tend to be higher in rivers in which the fl ow has
been controlled by damming than in rivers that fl ow freely.

Request you to please provide an explanation of A vs D.
Thanks
H


Responding to a pm:

This is an explain the paradox question. What is the paradox? When there is less rainfall, rivers move slowly and hence algae levels are high. When there is extremely less rainfall, algae levels are low even in very slow moving rivers.

You would expect algae levels to be very high in case of very slow moving rivers but it is not so. You need to explain why the algae levels are low in very slow moving rivers in case of drought.

Option (A) is incorrect. It says that during drought, some species that feed on algae fall. This means algae's predators are few and hence, algae should thrive and their levels should be high. This certainly doesn't explain why their levels fall in case of drought.

Option (D) explains the paradox. In case of drought, rivers actually dry up completely for short intervals. Hence, all algae in the river would die out if it dries up. Therefore, the algae population would be low.
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Save $100 on Veritas Prep GMAT Courses And Admissions Consulting
Enroll now. Pay later. Take advantage of Veritas Prep's flexible payment plan options.

Veritas Prep Reviews

Senior Manager
Senior Manager
avatar
Joined: 16 Dec 2011
Posts: 453
Followers: 9

Kudos [?]: 146 [0], given: 70

Re: When there is less rainfall than normal, the water level of [#permalink] New post 19 Apr 2013, 05:31
imhimanshu wrote:
When there is less rainfall than normal, the water level of Australian rivers falls and the rivers flow more slowly. Because algae whose habitat is river water grow best in slow-moving water, the amount of algae per unit of water generally increases when there has been little rain. By contrast, however, following a period of extreme drought, algae levels are low even in very slow-moving river water.

Which of the following, if true, does most to explain the contrast described above?

(A) During periods of extreme drought, the populations of some of the species that feed on algae tend to fall.
(B) The more slowly water moves, the more conducive its temperature is to the growth of algae.
(C) When algae populations reach very high levels, conditions within the river can become toxic for some of the other species that normally live there.
(D) Australian rivers dry up completely for short intervals in periods of extreme drought.
(E) Except during periods of extreme drought, algae levels tend to be higher in rivers in which the flow has been controlled by damming than in rivers that flow freely.

Premises:
(1) Habitat of algae is river water.
(2) Algae grow best in slow-moving water, when there is less rainfall than normal.
(3) After extreme drought, even in very slow-moving river water, algae levels are low.

Question is to resolve the apparent paradox on low level of algae in slow-moving water when it is after extreme drought.

A) If number of algae-eaters become less, algae level is supposed to be higher. Does not give any information on why algae level becomes lower following drought.
B) This says how algae level can be higher. There is no information on why algae level becomes lower following drought.
C) There is no given on how living condition of other species can affect algae level.
D) The statement implies that dry riverbed, which does not provide normal living condition for algae, triggers death of algae to some extent. Immediately after death of some algae, even though there is very slow-moving river water following recovery from drought, it is natural that algae level would be low. The given information here resolves the paradox.
E) There is no information on the factors affecting given situation, i.e., algae level, following a period of extreme drought, in slow-moving river water.

Correct answer is D.
Verbal Forum Moderator
Verbal Forum Moderator
User avatar
Joined: 15 Jun 2012
Posts: 1120
Location: United States
Followers: 136

Kudos [?]: 1374 [0], given: 122

Re: When there is less rainfall than normal, the water level of [#permalink] New post 19 Apr 2013, 15:55
imhimanshu wrote:
When there is less rainfall than normal, the water level of Australian rivers falls and the rivers flow more slowly. Because algae whose habitat is river water grow best in slow-moving water, the amount of algae per unit of water generally increases when there has been little rain. By contrast, however, following a period of extreme drought, algae levels are low even in very slow-moving river water.

Which of the following, if true, does most to explain the contrast described above?

(A) During periods of extreme drought, the populations of some of the species that feed on algae tend to fall.
(B) The more slowly water moves, the more conducive its temperature is to the growth of algae.
(C) When algae populations reach very high levels, conditions within the river can become toxic for some of the other species that normally live there.
(D) Australian rivers dry up completely for short intervals in periods of extreme drought.
(E) Except during periods of extreme drought, algae levels tend to be higher in rivers in which the flow has been controlled by damming than in rivers that flow freely.

[Reveal] Spoiler:
Request you to please provide an explanation of A vs D.
Thanks
H


A cannot be the answer. if populations of some of the species that feed on algae tend to fall, algae levels must increase. A is the opposite answer.
KEY here is algae grow best in slow-moving water, if there's no water, algae cannot grow. Hence, D is correct.

Hope it helps.
_________________

Please +1 KUDO if my post helps. Thank you.

"Designing cars consumes you; it has a hold on your spirit which is incredibly powerful. It's not something you can do part time, you have do it with all your heart and soul or you're going to get it wrong."

Chris Bangle - Former BMV Chief of Design.

Senior Manager
Senior Manager
avatar
Joined: 06 Aug 2011
Posts: 409
Followers: 2

Kudos [?]: 67 [0], given: 82

Re: When there is less rainfall than normal, the water level of [#permalink] New post 15 Feb 2014, 00:52
its D.. bridges the gap b/w two given situations..

algae population increases in drough condition


Australian rivers dry up completely for short intervals in periods of extreme drought.


algae population didnt increase in extreme drought condition



what do happen in extreme drought condition for that algae population didnt increase..highlighted words fill the gap and resolve it !
_________________

Bole So Nehal.. Sat Siri Akal.. Waheguru ji help me to get 700+ score !

Intern
Intern
User avatar
Joined: 11 Jun 2011
Posts: 32
Location: India
GPA: 3.7
WE: Business Development (Retail Banking)
Followers: 0

Kudos [?]: 3 [0], given: 4

Re: When there is less rainfall than normal, the water level of [#permalink] New post 15 Feb 2014, 09:55
imhimanshu wrote:
When there is less rainfall than normal, the water level of Australian rivers falls and the rivers flow more slowly. Because algae whose habitat is river water grow best in slow-moving water, the amount of algae per unit of water generally increases when there has been little rain. By contrast, however, following a period of extreme drought, algae levels are low even in very slow-moving river water.


Less Rainfall ---- > Water Level of Australia falls -------> Rivers flow slowly -------- > Increase in amount of algae per unit area.

Extreme drought ------- > Level of algae low even in slow moving water.

Which of the following, if true, does most to explain the contrast described above?

(A) During periods of extreme drought, the populations of some of the species that feed on algae tend to fall.

Irrelevant.

(B) The more slowly water moves, the more conducive its temperature is to the growth of algae.

Irrelevant.

(C) When algae populations reach very high levels, conditions within the river can become toxic for some of the other species that normally live there.

Irrelevant.

(D) Australian rivers dry up completely for short intervals in periods of extreme drought.

If rivers dry up completely for short periods , then there must be increased algae population during that period.

(E) Except during periods of extreme drought, algae levels tend to be higher in rivers in which the flow has been controlled by damming than in rivers that flow freely.

Out of scope and irrelevant.
Re: When there is less rainfall than normal, the water level of   [#permalink] 15 Feb 2014, 09:55
    Similar topics Author Replies Last post
Similar
Topics:
rainfall Minheequang 9 16 May 2009, 03:52
Experts publish their posts in the topic Rainfall puma 7 17 May 2008, 23:54
X is positive interger less than 500.When x is divided by 7 javed 7 19 May 2007, 04:45
x is a positive integer less than 500. When x is divided by Paayal 10 05 Nov 2006, 12:47
A cuboid pool, when it is half full, the water level height joemama142000 6 14 Apr 2006, 17:49
Display posts from previous: Sort by

When there is less rainfall than normal, the water level of

  Question banks Downloads My Bookmarks Reviews Important topics  


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

Powered by phpBB © phpBB Group and phpBB SEO

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®.