Whales originated in the freshwater lakes and rivers

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Whales originated in the freshwater lakes and rivers of ancient Asia about sixty million years ago. Not until about ten million years later did species of whales develop specialized kidneys enabling them to drink salt water. Although fossil evidence shows that some early whale species that lacked such kidneys sometimes swam in the Earth's saltwater oceans, these species must have had to return frequently to freshwater rivers to drink. Which of the following is most strongly supported by the information given?

A. Fossils of whale species dating from between sixty million and fifty million years ago will not be found on continents that were at the time separated from ancient Asia by wide expanses of ocean.

B. Among whale fossils that date from later than about fifty million years ago, none are fossils of whale species that drank only fresh water.

C. Fossils of whale species that drank fresh water will not be found in close proximity to fossils of whale species that drank salt water.

D. The earliest whales that drank salt water differed from fresh-water-drinking whales only in their possession of specialized kidneys.

E. Between sixty million and fifty million years ago, the freshwater lakes and rivers in which whales originated were gradually invaded by salt water.

[spoiler]OA: We need to find the conclusion of the above argument. I came to the answer as B but the same is wrong. I tried to solve the question in the following manner

C,D & E irrelevant
A I thought to be out of scope
B I thought meant that the phrase from later than about fifty million years ago means that option is talking about the years which came after 50 million years ago i.e for example today is year 2011 and if I decrease 50 years then it becomes 1961 and later means after year 1961,therefore, as the argument also said that special kidneys developed after 50 million years ago

Please correct me if I am wrong and help me in reaching the right answer choice[/spoiler]
Source: — Critical Reasoning |

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by MarkMeier20 » Sun Jul 31, 2011 5:58 am
I think it is A. What is OA?

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by jonathan123456 » Sun Jul 31, 2011 6:18 am
IMO A

A. Fossils of whale species dating from between sixty million and fifty million years ago will not be found on continents that were at the time separated from ancient Asia by wide expanses of ocean.
WHales cannot swim across the ocean (saltwater) since kidneys came only after 50 M yrs ago.
This seems correct.

B. Among whale fossils that date from later than about fifty million years ago, none are fossils of whale species that drank only fresh water.
A little over the top

C. Fossils of whale species that drank fresh water will not be found in close proximity to fossils of whale species that drank salt water.
No info on location of fossils in para

D. The earliest whales that drank salt water differed from fresh-water-drinking whales only in their possession of specialized kidneys.
A little over the top, para does not talk about other features besides kidneys

E. Between sixty million and fifty million years ago, the freshwater lakes and rivers in which whales originated were gradually invaded by salt water.
Over the top

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by aspirant2011 » Sun Jul 31, 2011 7:44 am
jonathan123456 wrote:IMO A

A. Fossils of whale species dating from between sixty million and fifty million years ago will not be found on continents that were at the time separated from ancient Asia by wide expanses of ocean.
WHales cannot swim across the ocean (saltwater) since kidneys came only after 50 M yrs ago.
This seems correct.

B. Among whale fossils that date from later than about fifty million years ago, none are fossils of whale species that drank only fresh water.
A little over the top

C. Fossils of whale species that drank fresh water will not be found in close proximity to fossils of whale species that drank salt water.
No info on location of fossils in para

D. The earliest whales that drank salt water differed from fresh-water-drinking whales only in their possession of specialized kidneys.
A little over the top, para does not talk about other features besides kidneys

E. Between sixty million and fifty million years ago, the freshwater lakes and rivers in which whales originated were gradually invaded by salt water.
Over the top
Hi Jonathan,

Can you please brief more on option B?????

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by jonathan123456 » Mon Aug 01, 2011 5:54 pm
Strong language used i.e none
We really cant say that all whales converted to salt water after 50 M yrs. It might have been a gradual change.

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by gmat25 » Mon Aug 01, 2011 7:23 pm
@aispirant

Op B

Among whale fossils that date from later than about fifty million years ago, none are fossils of whale species that drank only fresh water.

If the fossils found were date between fifty million years ago to ten million years ago...then according to the premises in the given argument, the fossils will of the whales who drink frest water only, as whales who can drink salt water evolved not before ten million years ago. Hence in that case Op B will not be correct.
Princeton Review CAT - 710(Q-51, V-37) --> silly mistakes screwed up my VERBAL

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by aspirant2011 » Tue Aug 02, 2011 6:36 pm
Thanks a lot guys, yup OA is A :-)

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by Joseph_Alexander » Fri Aug 01, 2014 1:32 am
A. Fossils of whale species dating from between sixty million and fifty million years ago will not be found on continents that were at the time separated from ancient Asia by wide expanses of ocean. OK - The conclusion must tie together two disparate claims: whales originated in Asia + species must have returned after swimming into salt water. This is the only conclusion that supports the authority of the claims. Take note of the "must"

B. Among whale fossils that date from later than about fifty million years ago, none are fossils of whale species that drank only fresh water. Reverse answer. This conclusion does not make sense after the premises given.

C. Fossils of whale species that drank fresh water will not be found in close proximity to fossils of whale species that drank salt water. Reverse answer. The fossils must be found in close proximity because "these species" must have had to return.

D. The earliest whales that drank salt water differed from fresh-water-drinking whales only in their possession of specialized kidneys. Could be true; shell game. It's tempting because indeed the kidneys must have been different. Even so, it need not be true. If it were true, it would need different support that what is provided.

E. Between sixty million and fifty million years ago, the freshwater lakes and rivers in which whales originated were gradually invaded by salt water. Could be true. If there freshwater lakes were not invaded by salt water, it is still possible that whale's kidney evolved because of a different cause.