Whales originated in the freshwater lakes and rivers of ancient - 2

Question

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?

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.

KarishmaB · Accepted Answer

Premises : - 60 million yrs ago, whales originated in freshwater (which means lakes and rivers) of Asia - Special kidneys that allowed whales to drink salt water evolved 50 million yrs ago. - Sometimes whales without special kidneys swam into saltwater but they had to return frequently to freshwater. Think about your geography - Continents are separated by huge saltwater oceans. A continent has lakes and rivers (freshwater) within it. The rivers connect to the ocean. If you want to travel from Asia to North America by water, you will need to go through the huge ocean between them. 60 million years ago, whales originated in Asia's freshwater so they were in the continent of Asia. They did not have special kidneys so they could not travel across the ocean. Even if they did enter the ocean, they needed to return back to the freshwater of Asia. Point is, they couldn't swim far from Asia. Till 50 million yrs ago, special kidneys did not develop. So for the 10 million yrs from 60 million to 50 million yrs ago, whales couldn't leave the coast of Asia and swim far. So they couldn't reach the continents far from Asia separated by saltwater oceans. (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. Answer (A) (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.   We know that whales developed specialised kidneys about 50 million years ago. But did all whales without these kidneys vanish at that time, we don’t know.    (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.   Nothing suggests this in the argument.   (D) The earliest whales that drank salt water differed from fresh-water-drinking whales only in their possession of specialized kidneys.   The argument doesn’t suggest this.    (E) Between sixty million and fifty million years ago, the freshwater lakes and rivers in which whales originated were gradually invaded by salt water. Again, the argument does not suggest this. We do not know what prompted the whales to develop special kidneys. Discussion on Inference Questions: https://youtu.be/PMnU9ULdSfs

scorpionz · Answer

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.
 Clearly supports the statement from the prompt that although some whales did swim in salt water oceans, they had to return to freshwater rivers to drink. Hence it is implied that whales could not have travelled vast expanses of oceans. Consequently fossils of whales cannot be found in such continents that were very far from Asia

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.
 Contradicts the information in the prompt that only around 10 million years ago saltwater whales started emerging. Also, emergence of saltwater whales does not mean that freshwater whales ceased to exist

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.
 Irrelevant. Nothing in the prompt supports or contradicts this.

D. The earliest whales that drank salt water differed from fresh-water-drinking whales only in their possession of specialized kidneys.
 Nothing in the prompt supports this. Specialized kidneys has been mentioned as an attribute of saltwater whales, but not the ONLY attribute.

E. Between sixty million and fifty million years ago, the freshwater lakes and rivers in which whales originated were gradually invaded by salt water.
 Irrelevant. Nothing in the prompt supports or contradicts this.

tuanquang269 · Answer

I this choice A is more stronger. This choice prove that the whale cannot move to another continent before they develop kidney (absorb salt water)

In choice C, some of you may assume that each whale species will live in their own habitat, salt water or fresh water => prove that they develop super kidney, but it does not infer that whales swim ONLY in their own habitat. They can go around :D>

mejia401 · Answer

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.

KyleWiddison · Answer

I like this question. There aren't many people who have worked the problem yet, but it seems to be tricking most people.

Remember what you are trying to do on the problem. The correct answer will be one that should be true (or must be true) based on the facts presented in the argument. This problem really emphasizes the importance of eliminating your way to the right answer. Eliminate the ones that don't have to be true and you are left with the answer (and you will realize then, if you didn't before, that is probably does have to be true)...

KW

vad3tha · Answer

I like the question too.
I have A and D left after eliminating B,C,E
The word "only" made D wrong

Answer is A

KyleWiddison · Answer

Eliminating down to two answers is super helpful on a question like this because in a quick read it would be easy to skip over the word "only" in choice D. With extra time to focus on two answer choices you give yourself a great chance to spot that error. If you were scrambling for time on this question you could easily miss that word and get this question wrong. Probably no accident that the word is found later in the sentence in a later answer choice.

Eliminate your way to the correct answer and be careful for little words like only, not, always, etc....

KW

KyleWiddison · Answer

I'm replying to a PM on this one. The question was how to eliminate answer choice C.

This question asks us to determine which choices is supported by the argument, or in other words we need to draw a conclusion. The correct answer, or conclusion, will be supported by the argument, which states: 1 - Whales started in fresh water (60 million yrs ago) 2 - they took 10 million years to get kidneys good for salt water 3 - some whales w/out these kidneys did go in salt water but they must have had to return to fresh water.

Choice C says there were no mammalian species able to drink salt water before 50 million years ago. The only information we have from the argument relates to whales. We are given no information about other mammals so this choice is not supported by the argument.

KW

Patronus · Answer

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.
 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.
 It is possible that atleast some did not venture into salt water, and stayed only in the fresh water lake. 
 
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.
 It is possible that area where salt water and fresh water died is the same, like some end of river/ river basin.
 
D. The earliest whales that drank salt water differed from fresh-water-drinking whales only in their possession of specialized kidneys.
 Just because we are not given any evidence that fresh water did not have 2 extra fins than salt water ones, does not mean they did not have.
Quite possible that had other differences too. 
 
E. Between sixty million and fifty million years ago, the freshwater lakes and rivers in which whales originated were gradually invaded by salt water.
 If the fresh water lakes were invaded by salt water, that would be all the more reason for the fresh water lakes to NOT return to that place again.
Please note that they got specialised kidneys from 50millions years ago onwards, so between 60-50million years ago, they had non-specialised kidney

arhumsid · Answer

Firstly, I would like to bring to notice here that this question is not a 'Strengthen' question but a 'Must be true/Inference' one. The tag to should be reconsidered if this makes sense.

I happened to see this question yesterday on my GMAT Prep Exam Pack-1; i am happy to have gotten this correct there. However, the one i saw on my test had a different choice at option D. Now, what made me think about this Strengthen/Inference difference in this question was that option. Here's the question:

Attachment:

Whales.png [ 35.93 KiB | Viewed 68425 times ]

Initially, i picked option D. I think that's an strengthener (though its no 100% consistent with one of the premises, it helps the conclusion). But soon realized that this question asks us to believe the argument ans asks us to validate the options (and not the opposite), and i chose A.

I have never seen (or at least noticed) any CR question with wrong answer that tests this.

I need expert's comments on this strengthener vs inference thing. Is my above reasoning correct?

KarishmaB · Answer

This is an inference question - Which of the following is supported by the information given?
So the argument supports one of the options. So the correct option provides the conclusion. 
Option (A) provides the conclusion.

A strengthen question would be framed something like this: Which of the following best supports the argument/author's position etc?
So here you are looking for a strengthener.

newconcept123 · Answer

It is interesting to use timeline to solve such problems.
Only answer A strengthen 
B is weaken and E is irrelevant

ashutoshsh · Answer

Hi! Thanks for this great explanation. I was completely stuck with this question but your explanation really helped, however i still feel little uncomfortable with the question stem. I think it is a type of question in which we have to mark an answer choice that strongly supports(not strengthen) by the argument. So generally we do not add up our own information, in fact we find out the support from the argument itself (with no our own assumptions). After reading your explanation i finally understood the question but i felt that its more of strengthening question. Because argument nowhere says that fossils WILL NOT be found. There can be many reason for the fossils to reach there or in fact anywhere. The only information we have about fossils are that they indicate that those fishes lacked such specialized kidneys. 
Since you know more about the question-types, do u think that word 'support' in the question stem justifies the question..or they should have used word 'strengthen' 
Thanks

KarishmaB · Answer

The question stem is:
"Which of the following is most strongly supported by the information given?"

So you need to find the option that is supported BY the argument. The argument supports one option. Hence, that option would be the inference.

The word "support" could indicate either strengthen or inference question type. If the argument supports the option, you are looking for an inference. If you need the option to support the argument, you are looking for a strengthener.

Nunuboy1994 · Answer

The reason option A is supported is because if it were true that whales had to constantly return to freshwater lakes then it is unlikely that they would live on continents that are far aware from a freshwater source which is basically what A is saying

yipmewmew · Answer

KarishmaB  I just have one doubt which none of the expert replies have addressed till now.

In option 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."

Does "later than fifty million years ago" mean something like 40 million years ago from the present or something like 70 million years ago from the present? Got confused by this and hence couldnt solve the question right.

KarishmaB · Answer

Imagine a timeline. 50 million years ago is a point on that timeline. Later than that means the time after that. So 40 million years ago, 30 million years ago, today...

ChiranjeevSingh · Answer

Passage Analysis

Whales originated in the freshwater lakes and rivers of ancient Asia about sixty million years ago.

This statement gives us two key pieces of information about the origin of whales:

Where?  In the freshwater lakes and rivers of ancient Asia.  
   When?  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.

Let's break this down piece by piece. "Ten million years later" means ten million years after their origin, so about fifty million years ago. The sentence says "not until fifty million years ago did something happen."

What did not happen until then? Whales did not develop specialized kidneys enabling them to drink salt water.

Did whales develop kidneys at exactly fifty million years ago? We cannot say that. Consider this example: "Raj did not wake up until 10 AM." This means we know for sure he was asleep right up to 10 AM. But we don't know if he woke up at 10 AM or after.

You may wonder why the author then says specifically 10 AM. This is because the author's knowledge might be limited to that point. For example, the author might have checked on Raj at 10 AM and found him sleeping. So, the statement "he did not wake up until 10 AM" is a statement of fact up to that point. It does not allow us to conclude what happened after.

Similarly, from the passage, we can only be sure that  before  fifty million years ago, whales did not have these specialized kidneys. What happened at or after that time is not certain based on this sentence alone.

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.

This sentence describes the behavior and limitations of the " early  whale species that lacked such kidneys"—that is, the whales living between 60 and 50 million years ago. It tells us two things:

The evidence shows that they did enter saltwater oceans.  
  However, they "must have had to return frequently to freshwater." This is logical based on their need to drink. (This implies they could not survive for long periods in areas without access to freshwater, such as the middle of a large ocean.)

Deconstructing the Question

Which of the following is most strongly supported by the information given?

The question asks for a statement that is most supported by the facts provided.

Options Evaluation

(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.

Correct.    This option talks about fossils of certain whale species. Which whale species? Species dating from between 60 million and 50 million years ago. Given the passage, what do we know about such species? They would not have had specialized kidneys to drink salt water.

The option says that fossils of these species will not be found on certain continents. Which continents? The continents that were at the time (between 60 and 50 million years ago) separated from ancient Asia (where whales originated) by "wide expanses of ocean." In other words, those continents that were very far away from the whales' place of origin, with a large ocean in between.

Thus, the option says that fossils of whales which could not drink salt water wouldn't be found on continents that were far away from ancient Asia. This seems logical, given the information in the passage that such whales would have to frequently return to freshwater rivers to drink. Therefore, those whales could not have traveled across vast expanses of ocean to reach such continents. It follows that their fossils will not be found on such continents. This option is  strongly supported .

(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.

Incorrect.    This option talks about whale fossils from a specific time period: "later than about fifty million years ago." So, this refers to the period  after which  some whales "could" have had specialized kidneys.

What does it say about these fossils? It says that "none" of them belong to whale species that drank "only fresh water." Can we say that freshwater-only whale species completely ceased to exist after the 50-million-year mark?

The passage does not support this. It allows the possibility that  some  species could have developed the ability to drink salt water after fifty million years ago. This does not mean that  all  species did, or that freshwater-only species died out. It is entirely possible that freshwater-only and saltwater-adapted species coexisted. Therefore, this option is incorrect.

(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.

Incorrect.    This option talks about the location of fossils. It states that fossils of freshwater-drinking whales will "not be found in close proximity" to fossils of saltwater-drinking whales - a strict geographical separation between the habitats of the two types of whales.

The passage states that the early freshwater-drinking whales "sometimes swam in the Earth's saltwater oceans," which means they lived in coastal zones where freshwater rivers meet the sea. A saltwater-adapted whale could certainly live in the same coastal salt water. Because they could have inhabited the same locations, it is plausible their fossils could be found close together. The idea that they will "not" be found in proximity is therefore not supported by the passage.

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

Incorrect.    This option discusses the biological differences between two groups of whales: the earliest saltwater-drinkers and the freshwater-drinkers.

It claims that the  only  difference between them was the "specialized kidneys." It means no other anatomical, physiological, or genetic differences existed between the two groups.

The passage does not provide enough information to support such a sweeping claim. It identifies the specialized kidney as the key adaptation for drinking salt water, but it never says it was the  only  adaptation or the only difference.

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

Incorrect.    This option says that during the first ten million years of whale evolution, the whales' original freshwater habitats were slowly taken over by salt water.

This is a statement about a change in the environment. However, the passage is about a change in the whales themselves. The passage says whales swam in salt water oceans or could have developed the kidneys to drink salt water. It says nothing about the saltwater environments moving into the whales' original homes.

Whales originated in the freshwater lakes and rivers of ancient - 2

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Whales originated in the freshwater lakes and rivers of ancient - 2

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