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 18 Jan 2017, 02:12

### 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

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

### Hide Tags

Director
Joined: 15 Aug 2005
Posts: 798
Location: Singapore
Followers: 2

Kudos [?]: 55 [0], given: 0

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

### Show Tags

11 Oct 2005, 16:07
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 cloudsâ€™ 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.

Which one of the following statements, if true, best helps to resolve the conflict between scientistsâ€™ expectations, based on the known behavior of oxygen-18, and the result of their measurements of the rain cloudsâ€™ 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.

Which one of the following inferences about an individual rain cloud is supported by the passage?

(A) Once it is formed over the Atlantic, the rain cloud contains more ordinary oxygen than oxygen-18.
(B) Once it has passed over the Amazon, the rain cloud contains a greater-than-normal percentage of oxygen-18.
(C) The clouds rainfall contains more oxygen-18 than ordinary oxygen.
(D) During a rainfall, the cloud must surrender the same percentage of its ordinary oxygen as of its oxygen-18.
(E) During a rainfall, the cloud must surrender more of its oxygen-l8 than it retains.
_________________

Cheers, Rahul.

If you have any questions
you can ask an expert
New!
Director
Joined: 21 Aug 2005
Posts: 793
Followers: 2

Kudos [?]: 24 [0], given: 0

### Show Tags

11 Oct 2005, 19:07
1. I think B
If rain clouds are equally replenished with O-18 by both forests and oceans, there is no reason why the results shouldn't be consistent.

2. E is the one that seems to follow logically based on the 2nd sentence of the argument.
Manager
Joined: 21 Sep 2005
Posts: 235
Followers: 2

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

### Show Tags

12 Oct 2005, 00:32
D
A
VP
Joined: 13 Jun 2004
Posts: 1118
Location: London, UK
Schools: Tuck'08
Followers: 7

Kudos [?]: 45 [0], given: 0

### Show Tags

12 Oct 2005, 02:12
1.B
2.B
Intern
Joined: 18 Aug 2005
Posts: 42
Followers: 1

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

### Show Tags

12 Oct 2005, 10:38
1. B
2. E
Director
Joined: 15 Aug 2005
Posts: 798
Location: Singapore
Followers: 2

Kudos [?]: 55 [0], given: 0

### Show Tags

13 Oct 2005, 19:48
OAs are B and A!
_________________

Cheers, Rahul.

13 Oct 2005, 19:48
Similar topics Replies Last post
Similar
Topics:
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
2 Oxygen-18 is a heavier-than-normal isotope of oxygen. In a 3 16 Apr 2008, 10:54
Oxygen-18 is a heavier-than-normal isotope of oxygen. In a 11 05 Feb 2007, 12:09
Display posts from previous: Sort by

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

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

 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®.