Some types of organisms originated through endosymbiosis, the engulfin

Question

Some types of organisms originated through endosymbiosis, the engulfing of one organism by another so that a part of the former becomes a functioning part of the latter. An unusual nucleomorph, a structure that contains DNA and resembles a cell nucleus, has been discovered within a plant known as a chlorarachniophyte. Two versions of a particular gene have been found in the DNA of this nucleomorph, and one would expect to find only a single version of this gene if the nucleomorph were not the remains of an engulfed organism’s nucleus.

Which one of the following is most strongly supported by the information above?

(A) Only organisms of types that originated through endosymbiosis contain nucleomorphs.
(B) A nucleomorph within the chlorarachniophyte holds all of the genetic material of some other organism.
(C) Nucleomorphs originated when an organism endosymbiotically engulfed a chlorarachniophyte.
(D) Two organisms will not undergo endosymbiosis unless at least one of them contains a nucleomorph.
(E) Chlorarachniophytes emerged as the result of two organisms having undergone endosymbiosis.

Bunuel · Accepted Answer

OFFICIAL EXPLANATION

The stimulus can be intimidating because it contains several formidable scientific terms, but as usual these terms are explained as the stimulus progresses. Let us take a moment to recap the information in this problem. The stimulus begins by defining endosymbiosis, which is when one organism engulfs another such that the “conquered” organism still functions. Next, we are told that a nucleomorph—a DNA-containing, nucleus-like structure—has been discovered in a plant known as a chlorarachniophyte. As the last sentence begins we are told that this nucleomorph contains two versions of a particular gene. The remainder of the final sentence is the key to the problem and it illustrates how the test makers force students to maintain an awareness of conditional indicators. The conditional relationship in the final sentence is contained in the following section of text: “one would expect to find only a single version of this gene if the nucleomorph were not the remains of an engulfed organism’s nucleus.” In the middle of this section of text the word “if” appears, and produces the following conditional relationship: R = nucleomorph is the remains of an engulfed organism’s nucleus, 1 = find only a single version of this gene ~R—>1. However, as we know from our discussion of the last sentence, there was not a single version of the gene but two versions. This is equivalent to the necessary condition not occurring: ~1. Combining the two above diagrams, if the necessary condition does not occur, then the contrapositive is enacted and we can conclude that the sufficient condition does not occur: R. We can see the contrapositive in action more clearly if we link the two conditions in an arrow diagram: ~1—>R. In GMAT problems, the contrapositive is often introduced in this fashion, where a premise is given that contains both a sufficient and necessary condition, and then the necessary condition is denied. Adding those two pieces together produces a conclusion via the contrapositive that the sufficient condition cannot occur, as the following summary reveals: Premise 1: ~R—>1, Premise 2: 1. Conclusion: R. Premise 2 and the conclusion link together in the traditional contrapositive relationship we have seen previously: ~1—>R. Thus, the contrapositive produces the inference that the nucleomorph is the remains of an engulfed organism’s nucleus. With this information in hand, we can combine some of the other elements in the stimulus. Given that the nucleomorph is part of the chlorarachniophyte and is the remains of an engulfed organism’s nucleus, we have strong evidence that the chlorarachniophyte came about as the result of endosymbiosis (the engulfing 
of one organism by another).  This is most clearly stated in answer choice (E), the correct answer.

Answer choice (A): This is an exaggerated answer: the word “only” at the beginning of the answer choice is too strong, and there is no evidence in the stimulus to suggest that a conditional relationship exists between endosymbiosis and nucleomorphs.

Answer choice (B): This is also an exaggerated answer: the word “all” in the middle of the answer choice is too strong.

Answer choice (C): The stimulus discusses one unusual nucleomorph whereas the answer choice attempts to make a general statement about all nucleomorphs. As such, the answer choice exaggerates the situation and is incorrect. Note that the first three answer choices in this problem all exaggerate some aspect of the stimulus. This is not surprising: in a stimulus with complex terminology, the test makers wisely attempt to prey upon that difficulty by presenting answers that have a degree of truth but go just a bit too far. These answer choices are attractive to a test taker who fails to lock down the facts of the stimulus.

Answer choice (D): This answer choice is similar to answer choice (A), and is incorrect for similar reasons: no conditional relationship is established where nucleomorphs are necessary for endosymbiosis.

bkk145 · Answer

Difficult to understand. Between C or E for me.
I go with E.

The stem says that N is found within C. Also, two versions of N are found within C due to the E process. To me, this means that C originates from the process of E.
A is out of scope
B is not right because N only contains genetic material of the one it engluf, not "all" genetic material within C.
D is out of scope
For C, N cannot possibly engulf C since N is in C engulfing another of the same in C.

mba1382 · Answer

IMO E

I actually took time in understanding the stem but then by POE I picked E.

Here is my reasoning:

A. Only organisms of types that originated through endosymbiosis contain nucleomorphs. -- Extreme and never indicated in the stem.
B. A nucleomorph within the chlorarachniophyte holds all of the genetic material of some other organism. --- Again seems extreme in stating all of the genetic material of some other organism and also wrong as it can't be deduced from the stem.
C. Nucleomorphs originated when an organism endosymbiotically engulfed a chlorarachniophyte. --- This too we can't deduce from the stem.
D. Two organisms will not undergo endosymbiosis unless at least one of them contains a nucleomorph.--- This too is wrong and kind of extreme too
E. Chlorarachniophytes emerged as the result of two organisms having undergone endosymbiosis. ---This is a rephrase of the stem info i.e. unusual nucleomorph, a structure that contains DNA and resembles a cell nucleus, has been discovered within a plant known as a chlorarachniophyte. Two versions of a particular gene have been found in the DNA of this nucleomorph

Good question indeed :-)

mikemcgarry · Answer

Dear msj1234567 , I'm happy to respond. :-)

I searched the web a little, looking for the source. This question may be an LSAT question --- it also has the feel of an LSAT question. That's OK. The arguments on the LSAT are way harder than GMAT CR, but if you can handle LSAT arguments, you are in good shape for GMAT CR. Which one of the following is most strongly supported by the information above? We want to draw a conclusion, something that must be true based on the passage. You may find this blog helpful: https://magoosh.com/gmat/2013/gmat-criti ... inference/ A. Only organisms of types that originated through endosymbiosis contain nucleomorphs . We don't know. Maybe most nucleomorphs arise from endosymbiosis, but a few in some totally unrelated species arise from a viral infection of something else. Such a possibility is not excluded by the argument, which only concerns the results of endosymbiosis. Thus, we can't be sure this is true. This is incorrect. B. A nucleomorph within the chlorarachniophyte holds all of the genetic material of some other organism . Maybe. Maybe it hold all, or most, or over 50%, or etc. We don't know. It definitely holds some, but "all" is too extreme. This is incorrect. C. Nucleomorphs originated when an organism endosymbiotically engulfed a chlorarachniophyte . Hmmm. Who engulfed whom? Was the chlorarachniophyte the "engulfer" or the "engulfee"? We don't know, and the passage gives us no clear basis on which to decide. This is incorrect. D. Two organisms will not undergo endosymbiosis unless at least one of them contains a nucleomorph . Hmmm. This is not clear. In my reading of the passage, it seemed like two organism with ordinary, run-of-the-mill nuclei, could merge and make a nucleomorph as a result of endosymbiosis. That part is definitely clear from the passage, that nucleomorphs result from endosymbiosis. Does one thing have to have a nucleomorph before endosymbiosis even begins? This is unclear. This answer is incorrect. E. Chlorarachniophytes emerged as the result of two organisms having undergone endosymbiosis . Well, the chlorarachniophytes have two versions of the same gene, which suggests that their nucleomorph resulted from endosymbiosis. We don't know who engulfed whom, but it seems quite clear that the resulting chlorarachniophyte came about from the endosymbiosis of two organism. It may be that one of those two was the chlorarachniophyte itself --- this choice leaves this possibility open. Nevertheless, the fact that the chlorarachniophyte as we now know it, with its nucleomorph, must be the result of endosymbiosis. That's indisputable. This is the correct answer. Does all this make sense? Mike :-)

KarishmaB · Answer

The information given in the argument is complicated due to the scientific terminology used. Try to make a relationship chart on your rough sheet which looks something like this:

Endosymbiosis - Engulfing of an organism though it serves some function inside the other's body.

So Chlora the plant contains unusual nucleomorph which suggests endosymbiosis.

Now all you need to do is run through the options.

A. Only organisms of types that originated through endosymbiosis contain nucleomorphs. - Not supported
B. A nucleomorph within the chlorarachniophyte holds all of the genetic material of some other organism. - All genetic material? We dont know
C. Nucleomorphs originated when an organism endosymbiotically engulfed a chlorarachniophyte. - Not supported
D. Two organisms will not undergo endosymbiosis unless at least one of them contains a nucleomorph. - Not supported
E. Chlorarachniophytes emerged as the result of two organisms having undergone endosymbiosis. - This is supported. This is what we inferred in our analysis too.

Answer (E)

hiteshahire22 · Answer

OA is E

The Arguments states :
1. Endosymbiosis is a process that involves 2 organisms (1st becomes a functioning part of the latter)
2. 'Unusual' Nucleomorph has been discovered in some plant : chlorarachniophyte and two versions of a particular gene have been found in the DNA of this Nuclemorph
3. If the nucleomorph was not associated with Endosymbiosis then only 1 version of gene would have been found.

Answer choices 
A) Only organisms of types that originated through endosymbiosis contain nucleomorphs. - This is a direct elimination as it states 'Only' those organisms contain Nucleomorphs that originated through endosymbiosis. 
(B) A nucleomorph within the chlorarachniophyte holds all of the genetic material of some other organism. - Not mentioned in the argument, totally out of scope
(C) Nucleomorphs originated when an organism endosymbiotically engulfed a chlorarachniophyte. - The nucleomorphs origination process is note explained or given in the argument.
(D) Two organisms will not undergo endosymbiosis unless at least one of them contains a nucleomorph. - Endosymbiosis process is not dependent on nucleomorph. 
(E) Chlorarachniophytes emerged as the result of two organisms having undergone endosymbiosis. -   Correct answer  choice -   Chlorarachniophytes - 2 versions of a particular gene - only possible with Endosymbiosis - 2 organisms.

anairamitch1804 · Answer

(A) Only organisms of types that originated 
through endosymbiosis contain 
nucleomorphs. - Not supported by the argument. Its a strong statement to make.

(B) A nucleomorph within the chlorarachniophyte 
holds all of the genetic material of some 
other organism. - Again not supported. Argument says nucleomorph contains the plants DNA not all genetic info of the other organism.

(C) Nucleomorphs originated when an organism 
endosymbiotically engulfed a 
chlorarachniophyte.- origination of nucleomorphs is not mentioned.

(D) Two organisms will not undergo endosymbiosis 
unless at least one of them contains a 
nucleomorph. - Not supported.

(E) Chlorarachniophytes emerged as the result of 
two organisms having undergone 
endosymbiosis. - supported in the argument. Check the last line. 
Quote:
Two versions of a particular gene have been found in the DNA of this nucleomorph, and one would expect to find only a single version of this gene if the nucleomorph were not the remains of an engulfed organism's nucleus.

unraveled · Answer

Some types of organisms originated through endosymbiosis, the engulfing of one organism by another so that a part of the former becomes a functioning part of the latter. An unusual nucleomorph, a structure that contains DNA and resembles a cell nucleus, has been discovered within a plant known as a chlorarachniophyte. Two versions of a particular gene have been found in the DNA of this nucleomorph, and one would expect to find only a single version of this gene if the nucleomorph were not the remains of an engulfed organism’s nucleus.

Which one of the following is most strongly supported by the information above?

(A)  Only  organisms of types that originated through endosymbiosis  contain nucleomorphs . - WRONG. Big claim that is not backed by the passage.
(B) A nucleomorph within the chlorarachniophyte holds  all of the genetic material  of some other organism. - WRONG. 'All' is extreme claim.
(C) Nucleomorphs  originated when an organism endosymbiotically engulfed  a chlorarachniophyte. - WRONG. Exact opposite of what is mentioned.
(D) Two organisms  will not undergo  endosymbiosis  unless at least one of them contains a nucleomorph . - WRONG. Two highlighted text are not certain.
(E) Chlorarachniophytes emerged as the result of two organisms having undergone endosymbiosis. - CORRECT. Looks fine as it doesn't contradict anything of the passage.

Answer E.

varshaaaaa · Answer

Hi,
Could someone please explain the diagram that has been mentioned in the explaination?(highlighted text). Or could you direct me to an article that will help me understand how conditional relationships work on the GMAT. 
Thanks!

VerbalBot · Answer

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Some types of organisms originated through endosymbiosis, the engulfin

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