Oxygen-18 is a heavier-than-normal isotope of oxygen. In a : GMAT Critical Reasoning (CR)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 17 Jan 2017, 02:23

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Oxygen-18 is a heavier-than-normal isotope of oxygen. In a

Author Message
TAGS:

### Hide Tags

Director
Joined: 06 Jan 2008
Posts: 555
Followers: 2

Kudos [?]: 351 [1] , given: 2

Oxygen-18 is a heavier-than-normal isotope of oxygen. In a [#permalink]

### Show Tags

16 Apr 2008, 10:54
1
KUDOS
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

Oxygen-18 is a heavier-than-normal isotope of oxygen. In a rain cloud, water molecules containing oxygen-18 are rarer than water molecules containing normal oxygen. But in rainfall, a higher proportion of all water molecules containing oxygen-18 than of all water molecules containing ordinary oxygen descends to earth. Consequently, scientists were surprised when measurements along the entire route of rain clouds’ passage from above the Atlantic Ocean, the site of their original formation, across the Amazon forests, where it rains almost daily, showed that the oxygen-18 content of each of the clouds remained fairly constant.
19. Which one of the following statements, if true, best helps to resolve the conflict between scientists’ expectations, based on the known behavior of oxygen-18, and the result of their measurements of the rain clouds’ oxygen-18 content?
(A) Rain clouds above tropical forests are poorer in oxygen-18 than rain clouds above unforested regions.
(B) Like the oceans, tropical rain forests can create or replenish rain clouds in the atmosphere above them.
(C) The amount of rainfall over the Amazon rain forests is exactly the same as the amount of rain originally collected in the clouds formed above the Atlantic Ocean.
(D) The amount of rain recycled back into the atmosphere from the leaves of forest vegetation is exactly the same as the amount of rain in river runoffs that is not recycled into the atmosphere.
(E) Oxygen-18 is not a good indicator of the effect of tropical rain forests on the atmosphere above them.
If you have any questions
New!
CEO
Joined: 17 May 2007
Posts: 2989
Followers: 60

Kudos [?]: 579 [0], given: 210

### Show Tags

16 Apr 2008, 15:35
A for me. Good question +1.
saravalli wrote:
Oxygen-18 is a heavier-than-normal isotope of oxygen. In a rain cloud, water molecules containing oxygen-18 are rarer than water molecules containing normal oxygen. But in rainfall, a higher proportion of all water molecules containing oxygen-18 than of all water molecules containing ordinary oxygen descends to earth [ reasoning 1]. Consequently, scientists were surprised when measurements along the entire route of rain clouds’ passage from above the Atlantic Ocean, the site of their original formation, across the Amazon forests, where it rains almost daily, showed that the oxygen-18 content of each of the clouds remained fairly constant [conclusion].
19. Which one of the following statements, if true, best helps to resolve the conflict between scientists’ expectations, based on the known behavior of oxygen-18, and the result of their measurements of the rain clouds’ oxygen-18 content?
(A) Rain clouds above tropical forests are poorer in oxygen-18 than rain clouds above unforested regions. [Good]
(B) Like the oceans, tropical rain forests can create or replenish rain clouds in the atmosphere above them. [trap alert - remember the arguement is all about oxygen-18 not about the replenishment of rain clouds]
(C) The amount of rainfall over the Amazon rain forests is exactly the same as the amount of rain originally collected in the clouds formed above the Atlantic Ocean. Irrelevant
(D) The amount of rain recycled back into the atmosphere from the leaves of forest vegetation is exactly the same as the amount of rain in river runoffs that is not recycled into the atmosphere. Irrelevant
(E) Oxygen-18 is not a good indicator of the effect of tropical rain forests on the atmosphere above them. - Irrelevant
Director
Joined: 06 Jan 2008
Posts: 555
Followers: 2

Kudos [?]: 351 [0], given: 2

### Show Tags

17 Apr 2008, 11:05
OA is B. can we discuss more.

Yesterday ,I took this test in LSAT-CR1000, and I got 17/24. Any comments on my performance?
Time: Oh yaa I took 3 Min for each question.
CEO
Joined: 17 May 2007
Posts: 2989
Followers: 60

Kudos [?]: 579 [1] , given: 210

### Show Tags

17 Apr 2008, 15:26
1
KUDOS
I narrowed it down to two A and B and sensed that B was a trap - ah well ... wasnt my best day yesterday in terms of CR answers. B does make sense when you think about it

Oh dont worry about the LSAT hit rate. LSAT ones are a lot more convoluted - they provide great reading practice.
Re: CR-Oxygen   [#permalink] 17 Apr 2008, 15:26
Similar topics Replies Last post
Similar
Topics:
Just a few years ago salmon could not survive in the oxygen 6 19 Jul 2011, 04:01
Oxygen-18 is a heavier-than-normal isotope of oxygen. In a 4 30 May 2009, 23:34
1 Ozone is a form of oxygen in which three atoms form a 7 26 Jun 2008, 23:20
Oxygen-18 is a heavier-than-normal isotope of oxygen. In a 9 16 Apr 2008, 10:55
Oxygen-18 is a heavier-than-normal isotope of oxygen. In a 11 05 Feb 2007, 12:09
Display posts from previous: Sort by