A new species of fish has just been discovered living in great numbers

Question

A new species of fish has just been discovered living in great numbers in the waters off Papua New Guinea. The fish exhibits some characteristics belonging to sharks, such as a cartilaginous skeleton. However, the fish also exhibits characteristics belonging to eels, such as a long, snake-like body. Because of the habitat where it was found and its obviously eel-like body, almost all scientists believe that the fish is an eel. But the cartilaginous skeleton puzzles them, since no known eel possesses one. So scientists are still unsure as to the fish's precise classification, but they agreed immediately that the most logical classification would be as either a shark or an eel.

The statements above, if true, most strongly support which of the following?

A. To be placed into a certain classification, a fish must possess all the characteristics of that classification.
B. Physical characteristics, such as skeletons, are scientists' primary means of classifying new species.
C. Some fish with cartilaginous skeletons are not sharks.
D. The waters off Papua New Guinea are generally hospitable to eels.
E. A fish cannot be both a shark and an eel.

KarishmaB · Accepted Answer

Responding to a pm:

We need to look for an option which we can infer/conclude from the argument. The argument must provide data to support it. Since most of the options have come up for discussion, let's discuss each one of them.

A.To be placed into a certain classification, a fish must possess all the characteristics of that classification.

We cannot infer this from the argument. In fact, we can say that 'a fish needn't possess all the characteristics of that classification' with more authority. Note this line: "Because of the habitat where it was found and its obviously eel-like body, almost all scientists believe that the fish is an eel." 
The scientists believe that the fish is an eel because of a couple of eel like characteristics. They are puzzled by one characteristic that this fish has which no eel has but other missing eel like characteristics doesn't seem to cause any problem at all. Hence we can certainly not conclude this statement.

B.Physical characteristics, such as skeletons, are scientists' primary means of classifying new species.

Again, we cannot infer this. We don't know the primary means of classifying new species. Scientists seem to be using physical characteristics e.g. eel like body, skeleton etc as well as habitat.

C.Some fish with cartilaginous skeletons are not sharks.

All we can say from the argument is that no eel has cartilaginous skeletons and some sharks have cartilaginous skeletons. We don't know whether some non-sharks have cartilaginous skeletons too. The new fish has not been classified yet. We don't know whether it is an eel or a shark or both. If it is classified as an eel, then we can say that some fish with cartilaginous skeletons are not sharks. If instead, it is classified as a shark, then we do not know whether there are some fish with cartilaginous skeletons that are not sharks. Hence, we cannot infer this.

D.The waters off Papua New Guinea are generally hospitable to eels.

We can infer this statement. The fish has been found in the waters off Papua New Guinea. The statement "Because of the habitat where it was found and its obviously eel-like body, almost all scientists believe that the fish is an eel." helps us infer that this habitat is suited to eels.

E.A fish cannot be both a shark and an eel.

The argument only says that the fish is either a shark or an eel. Recall that 'either or' construct implies 'at least one' in reasoning. Both are also possible. When we say 'I will get either a dog or a cat', it implies I will get at least one of the two and I could get both too. 
In any case, the argument only talks about this particular fish. It says that this fish is either a shark or an eel. It is certainly possible that there is some fish which is considered both a shark and an eel. The argument doesn't say that such a fish does not exist. At the end of the debate, the scientists may put this fish also in both the classifications. We cannot conclude that a fish cannot be both from this argument.

Answer (D)

nerd · Answer

ANswer:D, i think this is why, wasn't my first choice either

A.To be placed into a certain classification, a fish must possess all the characteristics of that classification.- wrong,no clear mention of how classification is done.
B.Physical characteristics, such as skeletons, are scientists' primary means of classifying new species.- may be one of the criteria..thsi also is wrong
C.Some fish with cartilaginous skeletons are not sharks.- there is a possibility there are others who qualify to be a shark.un clear- wrong
D.The waters off Papua New Guinea are generally hospitable to eels.- the paragraph clearly states that"because of the habitat.......the fish is a eel"- correct
E.A fish cannot be both a shark and an eel.- the possibility is not ruled out- this is only the most logiacl conclusin for this species.- not a direct conclusion.
Therefore the best answer is D

daviesj · Answer

Here's what Kaplan has to say about the OA:

Conclusion:   This is an inference question that asks us to draw a conclusion from the information provided. What must also be true given the stimulus?

Evidence:  Since we need to draw our own conclusion, we can use all facts provided in the argument as evidence.

The first sentence states that the new fish was discovered off the waters of Papua New Guinea. In addition, the sentence 4 states that the new fish shares its habitat with the eel. In combination, these two sentences indicate that eels also live in the waters off Papua New Guinea. So this region must be hospitable to eels, as stated in (D).

(A) doesn't follow from the information given. The last sentence implies that the new fish could be classified as a shark even though it does not have a cartilaginous skeleton Also, it is extreme in its use of the word all. With (B), the importance of physical characteristics relative to other characteristics is not discussed. With (C), if the new fish were to be classified as an eel, then we could conclude that at least one fish with a cartilaginous skeleton is not a shark. The stimulus, however, never says this. Furthermore, we aren't told anything about other fish classifications. And with (E), the last sentence states that the new fish will probably be classified as either a shark or an eel, but suggests nothing about an animal being both. Though this choice may seem true, we don't know for certain.

catennacio · Answer

Conclusion: Fish is EITHER shark OR eel. (A is either X or Y)

I too confidently marked E as I think it's a necessary assumption. E says it cannot be both, so it strengthens to the fact that it can only be one of the two type.

However OA is D, and as some explanation, D rules out the possibility that fish is shark, so it could be eel. I don't agree with this reasoning because the conclusion we need to support here is A is either X or Y. So if D says A leans toward X more, then it actually weakens the conclusion "A is either X or B" (since we don't know any other information, so possibility here is 50/50), as it leans afar from the possibility of the fact that A could be Y.

Tough one, experts please help. What is the source of this question?

daviesj · Answer

Differentiating an inference from an assumption can be a difficult because the definition of each refers to what "Must be true". 
But the difference is simple: An inference is what follows from an conclusion, where as an assumption is what is taken for granted to make a conclusion. In other words, an assumption occurs "before" the argument, that is, while the argument is being made. An inference is made "after" the argument is completed.

is it convincing enough?

KarishmaB · Answer

A 'support' question can be an inference question or a strengthen question. You need to carefully observe the question to figure out what type of question it is.

The statements above, if true, most strongly support which of the following?
- Inference question - The statements given in the argument are supporting an option. The option must be the inference/conclusion.

Which of the following, if true, supports the argument given above?
- Strengthen question - We are looking for the option that supports the argument i.e. supports the conclusion. Here we already have the conclusion and we want to strengthen it.

plumber250 · Answer

Hi Prateek,

Let me see if I can help.

The issue with your answer C, is that no where in the passage does it suggest that there are other fish that are not sharks with a cartilaginous skeleton. In fact it says the opposite - the problem scientists are having is that they've not come across such a thing in an eel like fish before.

D is correct, because you can infer that because many scientists are happy to call this fish an eel, that eel's must be found close to Papa New Guinea.

Does that make sense?

James

Paris75 · Answer

I discussed this question with my teacher and his answer was direct: this will never be on a GMAT exam!

The reason he evoked is that " generally " is not correct in the answer choices.  Generally  could mean that only 60% of the waters off Papua new Guinea are hospitable to eels and therefore, the conclusion is not obvious and is ambiguous!

A. To be placed into a certain classification, a fish must possess all the characteristics of that classification. - " All " is incorrect -  Wrong 
B. Physical characteristics, such as skeletons, are scientists' primary means of classifying new species. - Not stated -  Wrong 
C. Some fish with cartilaginous skeletons are not sharks. - Can not logically conclued this from text -  Wrong

The answer E is an extrapolation that is too  extreme  to be stated. "A fish (meaning all the kind of fish) cannot be a shark and an eel"

Answer D is correct but really badly formulated...

This will never be on the GMAT exam...

bb61 · Answer

I fell in the trap of D as well. but after checking LSAT, I find out that "either/or" means "at least one of the two". this definition implicitly allows that both elements occur... therefore, D is the correct answer.

Enbee11 · Answer

A new species of fish has just been discovered living in great numbers in the waters off Papua New Guinea. The fish exhibits some characteristics belonging to sharks, such as a cartilaginous skeleton. However, the fish also exhibits characteristics belonging to eels, such as a long, snake-like body. Because of the habitat where it was found and its obviously eel-like body, almost all scientists believe that the fish is an eel. But the cartilaginous skeleton puzzles them, since no known eel possesses one. So scientists are still unsure as to the fish's precise classification, but they agreed immediately that the most logical classification would be as either a shark or an eel.

The statements above, if true, most strongly support which of the following?

A. To be placed into a certain classification, a fish must possess all the characteristics of that classification.
B. Physical characteristics, such as skeletons, are scientists' primary means of classifying new species.
C. Some fish with cartilaginous skeletons are not sharks.
D. The waters off Papua New Guinea are generally hospitable to eels.
E. A fish cannot be both a shark and an eel.

Start with main points of abstract
1. New fish found near Papua New Guinea (PNG)
2. New fish Similar to Shark
3. Scientist belive that new fish = eel because   where it lives   & similar charcterstics as eel possessed
but scientist are puzzeled over skelton so the New fish is either shark or eel 
Now look at options:
A. To be placed into a certain classification, a fish must possess  all the characteristics of that classification .= Perhaps the most contending option but " the charcterstics of that classification" extreme the answer to narrow the category= keep alive as strong point
B. Physical characteristics, such as skeletons, are scientists' primary means of classifying new species.=That is not true since scientist look for body structure as well= so wrong
C. Some fish with cartilaginous skeletons are not sharks.= out of scope cauz primarily focused on property of matter= so out of space
D. The waters off Papua New Guinea are generally hospitable to eels.= this looks the probable answer because above the above bold + underline line states that the water is hospitable
E. A fish cannot be both a shark and an eel.= The fish can be both but since the puzzling dot is Skelton so cannot justify the statement= hence wrong

So choice left A & D 
A= too extreme to classify/ justify the correctness

Answer= D

Amit1408GMAThunk · Answer

According to me what explanation bb61 gave is more logical.

It says 'Either A or B' indicates - only A or only B or both A and B.

So option of both A and B are still open and the stimulus does not infer option E specifically.

Hence E is eliminated and option D is the best answer choice.

Hope this helps.

ENGRTOMBA2018 · Answer

B can not be the correct inference because of 2 words : "new species" and "primary" both these words are very particular in their meanings while the argument nowhere talks about what is the primary method of classification or whether ALL species are classified in this way.

E also uses the same trap of talking about a thing that "might be true" but is always true? We cant say based on just 1 example of the given species in question.Not talking about a species that might be both eel and a shark does not mean that it doesn't exist or at least is not mentioned such.

Such options that talk about absolute terms should make you extremely cautious and are usually incorrect as most of the arguments tend to not go to extremes. These options are classic traps in inference questions.

nikhiljd · Answer

For D to be answer ... and i think it can be inferred from the following statement in the passage.
A new species of fish has just been discovered living in great numbers in the waters off Papua New Guinea. The fish exhibits some characteristics belonging to sharks, such as a cartilaginous skeleton. However, the fish also exhibits characteristics belonging to eels, such as a long, snake-like body. Because of the habitat where it was found and its obviously eel-like body, almost all scientists believe that the fish is an eel. But the cartilaginous skeleton puzzles them, since no known eel possesses one. So scientists are still unsure as to the fish's precise classification, but they agreed immediately that the most logical classification would be as either a shark or an eel.

hence we can infer that the region is eel friendly ..HOW??? The scientists hypothesis that since this eel like looking fish is found in eel populated area ,it has to be an eel species ..
BTW I too choose a different answer(B) and then I read the passage closely and deduced this...
I may be wrong...
Damm these inference questions....

Ekland · Answer

nikhiljd  you are not wrong.
You were very close.

chetan2u · Answer

Hi,

Sorry, did not see your earlier post of 12 april...
Nikhil is bang on with his explanation..

Rather even the first time you read it, you should be slightly wary of --
  Because of the habitat where it was found and its obviously eel-like body, almost all scientists believe that the fish is an eel ..
We are talking of characteristics and then all of a sudden the words " Because of the habitat where it was found" are spoken, which do not have otherwise any place in the argument..

And as it turns out, the Q asks for some inference and this HABITAT comes up once again..

And, Ofcourse, the argument says that one of the reasons the new species should be classified as EEL is because of its habitat... so the place must be home to EELs..

Debashis Roy · Answer

VeritasKarishma   GMATNinja 
Can point (C) be an assumption for this argument?

KarishmaB · Answer

C.Some fish with cartilaginous skeletons are not sharks.

No, option (C) is not an assumption.

All we can say from the argument is that no eel has cartilaginous skeletons. 
We can also say that some sharks have cartilaginous skeletons. We don't know whether some non-sharks have cartilaginous skeletons too. 
Cartilaginous skeleton is an example of "shark characteristics" that the new fish possesses. Does this characteristic belong to only sharks? we can't say. 
The scientists are confused on how to classify the new fish because it has some characteristics of both - an eel and a shark. The argument makes no assumption about any one characteristic belonging to only one kind of fish.

Balkrishna · Answer

Hi  VeritasKarishma ,

Doesn't "either or" used when one can take only one option and not both?

For example, I want to go to either Asgard or Krypton. From this example, I can say that I will go to Asgard (and not Krypton) or I will go to Krypton (And not Asgard).

Can you please help me to resolve this doubt?

Thank you.

KarishmaB · Answer

In day to day language, either or usually implies one or the other but not both. But not so in logic. In logic, "either or" means "at least one of the two".

"I will go to either Asgard or Krypton" means I will go to at least one of these places and I could go to both too.

A new species of fish has just been discovered living in great numbers

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A new species of fish has just been discovered living in great numbers

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