It was once assumed that all living things could be divided into two

Question

It was once assumed that all living things could be divided into two fundamental and exhaustive categories. Multicellular plants and animals, as well as many unicellular organisms, are eukaryotic—their large, complex cells have a well-formed nucleus and many organelles. On the other hand, the true bacteria are prokaryotic cell, which are simple and lack a nucleus. The distinction between eukaryotes and bacteria, initially defined in terms of subcellular structures visible with a microscope, was ultimately carried to the molecular level. Here prokaryotic and eukaryotic cells have many features in common. For instance, they translate genetic information into proteins according to the same type of genetic coding. But even where the molecular processes are the same, the details in the two forms are different and characteristic of the respective forms. For example, the amino acid sequences of various enzymes tend to be typically prokaryotic or eukaryotic. The differences between the groups and the similarities within each group made it seem certain to most biologists that the tree of life had only two stems. Moreover, arguments pointing out the extent of both structural and functional differences between eukaryotes and true bacteria convinced many biologists that the precursors of the eukaryotes must have diverged from the common ancestor before the bacteria arose.

Although much of this picture has been sustained by more recent research, it seems fundamentally wrong in one respect. Among the bacteria, there are organisms that are significantly different both from the cells of eukaryotes and from the true bacteria, and it now appears that there are three stems in the tree of life. New techniques for determining the molecular sequence of the RNA of organisms have produced evolutionary information about the degree to which organisms are related, the time since they diverged from a common ancestor, and the reconstruction of ancestral versions of genes. These techniques have strongly suggested that although the true bacteria indeed form a large coherent group, certain other bacteria, the archaebacteria, which are also prokaryotes and which resemble true bacteria, represent a distinct evolutionary branch that far antedates the common ancestor of all true bacteria.

1. The passage is primarily concerned with

(A) detailing the evidence that has led most biologists to replace the trichotomous picture of living organisms with a dichotomous one
(B) outlining the factors that have contributed to the current hypothesis concerning the number of basic categories of living organisms
(C) evaluating experiments that have resulted in proof that the prokaryotes are more ancient than had been expected
(D) summarizing the differences in structure and function found among true bacteria, archaebacteria, and eukaryotes
(E) formulating a hypothesis about the mechanisms of evolution that resulted in the ancestors of the prokaryotes

2. According to the passage, investigations of eukaryotic and prokaryotic cells at the molecular level supported the conclusion that

(A) most eukaryotic organisms are unicellular
(B) complex cells have well-formed nuclei
(C) prokaryotes and eukaryotes form two fundamental categories
(D) subcellular structures are visible with a microscope
(E) prokaryotic and eukaryotic cells have similar enzymes

3. According to the passage, which of the following statements about the two-category hypothesis is likely to be true?

(A) It is promising because it explains the presence of true bacteria-like organisms such as organelles in eukaryotic cells.
(B) It is promising because it explains why eukaryotic cells, unlike prokaryotic cells, tend to form multicellular organisms.
(C) It is flawed because it fails to account for the great variety among eukaryotic organisms.
(D) It is flawed because it fails to account for the similarity between prokaryotes and eukaryotes
(E) It is flawed because it fails to recognize an important distinction among prokaryotes.

4. It can be inferred from the passage that which of the following have recently been compared in order to clarify the fundamental classifications of living things?

(A) The genetic coding in true bacteria and that in other prokaryotes
(B) The organelle structures of archaebacteria, true bacteria, and eukaryotes
(C) The cellular structures of multicellular organisms and unicellular organisms
(D) The molecular sequences in eukaryotic RNA, true bacterial RNA, and archaebacterial RNA
(E) The amino acid sequences in enzymes of various eukaryotic species and those of enzymes in archaebacterial species

5. If the “new techniques” mentioned in line 31 were applied in studies of biological classifications other than bacteria, which of the following is most likely?

(A) Some of those classifications will have to be reevaluated.
(B) Many species of bacteria will be reclassified.
(C) It will be determined that there are four main categories of living things rather than three.
(D) It will be found that true bacteria are much older than eukaryotes
(E) It will be found that there is a common ancestor of the eukaryotes, archaebacteria, and true bacteria.

6. According to the passage, researchers working under the two-category hypothesis were correct in thinking that

(A) prokaryotes form a coherent group
(B) the common ancestor of all living things had complex properties
(C) eukaryotes are fundamentally different from true bacteria
(D) true bacteria are just as complex as eukaryotes
(E) ancestral versions of eukaryotic genes functioned differently from their modern counterparts

7. All of the following statements are supported by the passage EXCEPT:

(A) True bacteria form a distinct evolutionary group.
(B) Archaebacteria are prokaryotes that resemble true bacteria.
(C) True bacteria and eukaryotes employ similar types of genetic coding.
(D) True bacteria and eukaryotes are distinguishable at the subcellular level
(E) Amino acid sequences of enzymes are uniform for eukaryotic and prokaryotic organisms.

8. The author’s attitude toward the view that living things are divided into three categories is best described as one of

(A) tentative acceptance
(B) mild skepticism
(C) limited denial
(D) studious criticism
(E) whole hearted endorsement

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Attachment:

File comment: Archaebacteria By Carl R. Woese (SCIENTIFIC AMERICAN
June 1981)

Archaebacteria.pdf [1.16 MiB]
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Show Answer Question #1

Official Answer

B

Show Answer Question #2

Official Answer

C

Show Answer Question #3

Official Answer

E

Show Answer Question #4

Official Answer

D

Show Answer Question #5

Official Answer

A

Show Answer Question #6

Official Answer

C

Show Answer Question #7

Official Answer

E

Show Answer Question #8

Official Answer

A

abhijit_sen · Accepted Answer

Notes:  
  Para 1:   Two type of living organism. Muti Cellular: Eukaryotic (Complex Cell and well formed nucleus). True Bacteria:Prokrayotic (lack nucleus). Tree of life had only two stems.

Para 2:   Tree of life has 3 stems. Archebachetria far antedates common ancestors of true bacteria.

1. The passage is primarily concerned with
(A) detailing the evidence that has led most biologists to replace the trichotomous picture of living organisms with a dichotomous one
Wrong. Passage says other way round.
(B) outlining the factors that have contributed to the current hypothesis concerning the number of basic categories of living organisms
Correct.

(C) evaluating experiments that have resulted in proof that the prokaryotes are more ancient than had been expected
Wrong. Passage suggest Archebachetria are older than prokaryotes (true bacteria).

(D) summarizing the differences in structure and function found among true bacteria, archaebacteria, and eukaryotes
Wrong. First para discusses “differences in structure and function found among true bacteria, and eukaryotes”. Moreover it is not complete passage in itself.

(E) formulating a hypothesis about the mechanisms of evolution that resulted in the ancestors of the prokaryotes
Wrong. There is no hypothesis formulated. Only result of studies are given.

2. According to the passage, investigations of eukaryotic and prokaryotic cells at the molecular level supported the conclusion that
This is explained in first para. From “Here prokaryotic and eukaryotic cells have 
many features in common” to end of the para 1 it is all about molecular similarities and differences.
(A) most eukaryotic organisms are unicellular
Wrong. This is explained initially at start of the para but not with regard to molecular structure.

(B) complex cells have well-formed nuclei
Wrong. This is explained initially at start of the para but not with regard to molecular structure.

(C) prokaryotes and eukaryotes form two fundamental categories
Seems Correct. Para 1 says “The differences between the groups and the similarities within each group made it seem certain to most biologists that the tree of life had only two stems”

(D) subcellular structures are visible with a microscope
Question is asking about “molecular” level so nothing to do with “sub cellular” although this is true. As explained in para 1.

(E) prokaryotic and eukaryotic cells have similar enzymes
Wrong. Para 1 says “the amino acid sequences of various enzymes tend to be typically prokaryotic or eukaryotic” means they are different.

3. According to the passage, which of the following statements about the two-category hypothesis is likely to be true?
Referring notes we see para 1 tells “tree of life” has two stems, but para 2 tells that “tree of life” has 3 stems. So “two-category hypothesis” is not promising, it is flawed.

(A) It is promising because it explains the presence of true bacteria-like organisms such as organelles in eukaryotic cells.
Wrong

(B) It is promising because it explains why eukaryotic cells, unlike prokaryotic cells, tend to form multicellular organisms.
Wrong

(C) It is flawed because it fails to account for the great variety among eukaryotic organisms.
2 category hypotheses is false because there is 3 categories not because earlier hypothesis cannot account for eukaryotic organisms.

(D) It is flawed because it fails to account for the similarity between prokaryotes and eukaryotes
2 category hypotheses is false because there is 3 categories not because it fails to account for similarity. In fact study does says at few instances these two seems similar.

(E) It is flawed because it fails to recognize an important distinction among prokaryotes.
Seems Correct. There is a third divison which is kind of “prokaryotes” but predates it.

4. It can be inferred from the passage that which of the following have recently been compared in order to clarify the fundamental classifications of living things?
Para 2 says “New techniques for determining the molecular sequence of the RNA of organisms”. So most probably it is study of molecular sequences of RNA.
(A) The genetic coding in true bacteria and that in other prokaryotes
Wrong. “True Bacteria” and “prokaryotes” are same thing. But in all possibility study was done of all three structures.

(B) The organelle structures of archaebacteria, true bacteria, and eukaryotes
Hold it. Look promising.

(C) The cellular structures of multicellular organisms and unicellular organisms
Wrong. “Muticelluar” and “unicellular” are Eukaryotes only and we need all the 3 structures.
(D) The molecular sequences in eukaryotic RNA, true bacterial RNA, and archaebacterial RNA
Looks promising. I will drop B and select this as best choice.

(E) The amino acid sequences in enzymes of various eukaryotic species and those of enzymes in archaebacterial species
Wrong. May be true. But new study also concluded about “true bacteria” so I will discount this.

5. If the “new techniques” mentioned in line 31 were applied in studies of biological classifications other than bacteria, which of the following is most likely?
(A) Some of those classifications will have to be reevaluated.
Seems OK. As study of bacteria revealed different classification so there are chances that study of other life form may also yield similar support.

(B) Many species of bacteria will be reclassified.
It classified bacteria into 2 class not into many species. Moreover question is asking about “biological classifications other than bacteria” not on bacteria.

(C) It will be determined that there are four main categories of living things rather than three.
Wrong. May be true, may be not. Not supported. Moreover question is asking about “biological classifications other than bacteria” not on bacteria.

(D) It will be found that true bacteria are much older than eukaryotes
Wrong. May be true, may be not. Not supported. Moreover question is asking about “biological classifications other than bacteria” not on bacteria.

(E) It will be found that there is a common ancestor of the eukaryotes, archaebacteria, and true bacteria.
Wrong. May be true, may be not. Not supported. Moreover question is asking about “biological classifications other than bacteria” not on bacteria.

6. According to the passage, researchers working under the two-category hypothesis were correct in thinking that
(A) prokaryotes form a coherent group
Wrong not supported.

(B) the common ancestor of all living things had complex properties
Wrong. Not supported.

(C) eukaryotes are fundamentally different from true bacteria
Seems Correct.

(D) true bacteria are just as complex as eukaryotes
Wrong. Not supported.

(E) ancestral versions of eukaryotic genes functioned differently from their modern counterparts
Wrong. Not supported.

7. All of the following statements are supported by the passage EXCEPT:
(A) True bacteria form a distinct evolutionary group.
True. “there are organisms that are significantly different both from the cells of eukaryotes and from the true bacteria”
(B) Archaebacteria are prokaryotes that resemble true bacteria.
True. “the archae bacteria , which are also prokaryotes and which resemble true bacteria”
(C) True bacteria and eukaryotes employ similar types of genetic coding.
Ture. “RNA of organisms have produced evolutionary information about the degree to which organisms are related”
(D) True bacteria and eukaryotes are distinguishable at the subcellular level
True. “The distinction between eukaryotes and bacteria, initially defined in terms of sub cellular structures visible with a microscope”
(E) Amino acid sequences of enzymes are uniform for eukaryotic and prokaryotic organisms.
False (so correct answer). “the amino acid sequences of various enzymes 
tend to be typically prokaryotic or eukaryotic”

8. The author’s attitude toward the view that living things are divided into three categories is best described as one of
Para 2 says “it now appears that there are three stems in the tree of life”. Which inidiates that author is sort of accepting it.
(A) tentative acceptance
Correct.

(B) mild skepticism
Wrong. There is no point which indicates author is skeptic about the claim.

(C) limited denial
Wrong. Author is accepting it and not denying it.

(D) studious criticism
Wrong. Author is accepting it and not criticizing it.

(E) whole hearted endorsement
Wrong. Although author does accept it but no where in passage it suggest that author is very positive about it.

Buddy please post OAs. I would like to confirm my answers.

GMATNinja · Answer

Questions 5 & 8 After reading the passage for structure and purpose (more on that general concept here ), you should read the question carefully to understand precisely what you’re being asked to do. Then reference the passage as needed to formulate your answer to that question. Then go from A to E, using process of elimination to identify FOUR wrong answers. You'll be left with one correct answer. This questions asks us to apply our understanding of “new techniques” to other studies. We can’t really do this without being confident in our understanding of why “new techniques” are discussed in this passage, so let’s confirm that understanding first. The author mentions these “new techniques” because these techniques have enabled researchers to produce new information about the evolution of living things: the degree to which organisms are related the time since organisms diverged from a common ancestor the reconstruction of ancestral versions of genes As a result of using these techniques on true bacteria and eukaryotes, researchers have defined a new evolutionary branch in the tree of life, referred to as “archaebacteria.” Therefore, if we apply these techniques to another biological classification, we expect to learn something new regarding these indicators of ancestry, which would then make us rethink the classification. We want to use process of elimination every time we tackle a GMAT question, so let’s get to it! This fits our understanding of the new techniques and why the author brings them up. If the techniques are used to study other classifications, we could expect them to challenge some of those classifications just as they have challenged the two-branch “tree of life.” While the existing model hasn’t been totally disrupted (the author writes that “much of this picture has been sustained by more recent research”), re-evaluation of that model is necessary to make sense of the new evidence. Let’s keep (A) unless we see an even better answer choice. This choice goes overboard in its language. Did the new techniques lead to many species of bacteria to be reclassified ? No. The author’s language not this strong in degree, so let’s eliminate (B). This choice makes a very specific claim about the number of branches of life, but the significance of these new techniques is not that they increase the number of categories of living things. The author’s point is that these new techniques make us rethink evolutionary ancestry, which in turn makes us rethink existing classifications more broadly. Eliminate (C). There’s nothing in the passage to suggest that new techniques change our measurement of how old true bacteria and eukaryotes are. Eliminate (D). The passage states that archaebacteria “represent a distinct evolutionary branch that far antedates the common ancestor of all true bacteria. ” These techniques have already shown us that archaebacteria are on a branch distinct from the common ancestor of true bacteria, so eliminate (E). Choice (A) remains our best option. pikolo2510 , I think Masterscorp did a nice job of addressing your question, but I'm having fun with this one, so... I'll pile on, too.

Before analyzing answer choices, let’s review our understanding of the author’s point of view. The author spends paragraph 1 spelling out the two-branch model of our “tree of life,” recounting various types of evidence to show why this picture has been largely accepted. The author spends paragraph 2 describing a new development, noting that the two-branch mode “seems fundamentally wrong in one respect.” When discussing how new techniques have challenged the previous classifications, the author states that “it now appears that there are three stems in the tree of life,” and that new “techniques have strongly suggested that archaebacteria...represent a distinct evolutionary branch.” The author definitely agrees with the new research, but the language being used by the author is very measured. To write that new techniques “strongly suggest” a conclusion is to write from a somewhat tentative position, because “suggest” is not as definitive as “prove” or “confirm.” So we’re looking for the answer choice that mostly closely fits this tentative level of agreement. This fits the level of agreement with the new research that we’re looking for! Let’s keep (A) around unless we find something better. The author is definitely not skeptical. Eliminate (B). The author is definitely not denying the claim. Eliminate (C). The author is definitely not criticizing the claim. Eliminate (D). Analyzing choice (E) on its own merit, “whole hearted” is simply too strong to match the language used by the author. If the author were making a whole hearted endorsement, phrases like “seems fundamentally wrong” and “it now appears” would be replaced by phrases like “is surely and fundamentally wrong” and “it is now proven beyond a doubt.” Even stating that the techniques “strongly suggest” the existence of a third branch is not extreme enough to match the degree of a “whole hearted” endorsement. Something along the lines of “definitively confirm” would be a better fit, but we don’t see this in the author’s language. Consequently, we eliminate (E) and keep (A) as the correct choice. I hope this gigantic word salad helps!

ShashankDave · Answer

I did the 4th question wrong. Please explain why (A) is wrong and (D) correct. The information regarding this question is present in the last few lines of the passage. There has been mention of true bacteria and the new type of bacteria, but there hasn't been any discussion of eukaryotes. Also the method discussed involves "reconstruction of genes". This made me choose (A) over (D), even when D has the keyword "RNA" in it, the passage hasn't mentioned eukaryotes in the lines describing the comparison. Please help. Am I making a strategic mistake? Is my approach wrong here? Please help

GMATNinja · Answer

The recent research is discussed in the second paragraph. This research has suggested that "among the bacteria, there are organisms that are significantly different both from the cells of eukaryotes and from the true bacteria, and it now appears that there are three stems in the tree of life." This portion suggests that the recent research compared eukaryotes, true bacteria, and a third type of life (which is later identified as archaebacteria).

We are then told that "new techniques for determining the molecular sequence of the RNA of organisms have produced evolutionary information about..." So we are first told that recent research has led to a distinction between three types of life. We are then told that this recent research involved examining the molecular sequences of organisms' RNA. Thus, we can INFER that the recent research involved comparing the "molecular sequences in eukaryotic RNA, true bacterial RNA, and archaebacterial RNA" - choice (D).

As for choice (A), we are told in the first paragraph that "{at the molecular level} prokaryotic and eukaryotic cells have many features in common. For instance, they translate genetic information into proteins according to the  same type of genetic coding ". So if we were to compare the genetic coding of the prokaryotic and eukaryotic cells, we would find similarities, not differences. Unlike the recent research, comparing the genetic coding would NOT suggest that we need to further divide up the tree of life. Thus, choice (A) likely does not apply to the recent research.

So (D) is the best answer.

TheRzS · Answer

Hi  GMATNinja 
Would you be able to help me with couple of my queries please?

Firstly, a generic question.
To answer specific question, should I read the 5 choices first? or should I read the relevant part on the passage first and then read A to E?

Now, a specific question about this passage.

5. If the “new techniques” mentioned in line 31 were applied in studies of biological classifications other than bacteria, which of the following is most likely?
(A) Some of those classifications will have to be reevaluated.  CORRECT, I guess?   
(B) Many species of    bacteria    will be reclassified. -  OUT , since the Q mentions   "other than bacteria"  
(C) It will be determined that there are four main categories of living things rather than three. -  OUT , since passage clearly mentions   "three stems in the tree of life"   
(D) It will be found that true    bacteria    are much older than eukaryotes -  OUT , since the Q mentions   "other than bacteria"  
(E) It will be found that there is a common ancestor of the eukaryotes, archaebacteria, and true    bacteria   .  OUT , since the Q mentions   "other than bacteria"

The only way to get to A , it seems, is POE, since I cannot base the inference on something solid - something tangible.

Is it just me or inference questions are harder, In both CR and RC. Any plan on doing a CR video on inference/must be true/conclusion questions?
Really enjoyed your videos.

Thanks and regards

pikolo2510 · Answer

Hey  GMATNinja ,

Can you help to explain the last question of the RC?

I went for E because of the below lines

I author is not tentative to accept the new approach, rather is he is strongly pushing(positive) for the new approach. Hence I went for E.

can you share your thoughts?

Diya52 · Answer

In Question 7, I can see how E is the correct answer as it is not supported by the passage because of these lines "But even where the molecular processes are the same, the details in the two forms are different and characteristic of the respective forms. For example, the amino acid sequences of various enzymes tend to be typically prokaryotic or eukaryotic". But can someone tell me how does one prove choice A to be supported by the passage?

GMATNinja · Answer

The passage first explains that it was "once assumed" that life could be divided into two evolutionary branches: the eukaryotic branch and "true bacteria," which are prokaryotic.

Then, the passage amends this explanation to account for  three  evolutionary branches: the eukaryotic branch, the true bacteria branch, and another prokaryotic branch called archaebacteria.

Even in this amended explanation, true bacteria form their own distinct evolutionary group -- the only change is that an another group is added. (A) is supported by the information in the passage, so it is not the answer to question #7.

I hope that helps!

09173140521 · Answer

OG answer question "3"

The best answer is E. According to the passage, the two-category hypothesis, which assumed “that
all living things could be divided into two…categories,” (lines 1-2) now “seems fundamentally
wrong” (line 27) because it does not account for evidence that two kinds of prokaryotic organisms
exist: true bacteria and “a distinct evolutionary branch,” archaebateria (line 40). Thus, the
hypothesis is said to ignore an important distinction among prokaryotes, as E states. Choice A is
wrong because the passage does not even mention bacteria alike organisms existing within
eukaryotic cells. B contradict the passage, which states that “many unicellular organisms… are
eukaryotic.” C and D are wrong because each identifies as a flaw the failure to “account for”
conditions that the passage indicates the hypothesis accounted for

APOGEE · Answer

GMATNinja  In question number 6,i have extracted the correct answer using poe, but can someone please address how option c is inferred, is it from the first few lines of the first para -describing the structure of pro. and eukr. ??

egmat · Answer

Hi Apogee,

In the first paragraph, the author introduces the two category theory - all life is either eukaryotic or true bacteria (prokaryotic). We are then told how the differences between the two are not just observed at a microscopic level, but also at an even tinier level (molecular). Observation of the similarities and differences led the researchers to believe that there are only these 2 categories (eukaryote, true bacteria (prokaryote)).

Check this line too:

" Moreover, arguments pointing out the extent of both structural and functional differences between eukaryotes and true bacteria convinced many biologists that... "

Again - it is very clear that for the researchers/biologists who advocated the two category theory, eukaryotes and true bacteria are structurally and functionally different! So, as per the researchers, these are two fundamentally different types.

This is where option C is inferred from, as per me.

The next paragraph is essentially the author coming in and explaining the existence of a third category, archaebacteria - also prokaryotic, but distinct from true bacteria. This calls into question the notion that only two categories exist.  But it also does not in anyway change the notion that eukaryotes and true bacteria are different , it only adds a third category.

So, option C is perfectly valid as per the information in the passage - the researchers were indeed right in thinking that eukaryotes are fundamentally different from true bacteria. This is true as per the passage.

Hope this helps!

Regards,
Harsha

mSKR · Answer

GMATNinja VeritasKarishma : Please clarify doubt on Q7 for option A and E 1. the true bacteria are prokaryotic cell 2. the true bacteria indeed form a large coherent group, --> it means many varieties under this group 3. certain other bacteria, the archaebacteria, which are also prokaryotes and which resemble true bacteria, 3rd says that archaebacteria are prokaryotes and also true bacteria. As GMATNinja above explanation says: archaebacteria is prokaryotes --> means divided from prokaryotes but not from true bacteria According to my understanding , true bacteria is a coherent group but not evoluaitonary group I know I am wrong, please suggest what am I missing? the amino acid sequences of various enzymes tend to be typically prokaryotic or eukaryotic. it doesn't mean these sequences are UNIFORM So I choose E over A as A had already too much interpretation Please guide GMATNinja VeritasKarishma

KarishmaB · Answer

First Paragraph - All life can be divided into two evolutionary groups:

Eukaryotic - Multicellular plants and animals, as well as many unicellular organisms —their large, complex cells have a well-formed nucleus and many organelles.
Prokaryotic - True bacteria which are simple and lack a nucleus
They have differences on molecular level.

Second Paragraph - Recent study suggest 3 evolutionary branches:

Eukaryoptic
Prokaryoptic
Archaebacteria (which are also prokaryotes currently) represent a distinct evolutionary branch that far antedates the common ancestor of all true bacteria.
So the "Prokaryotic - True bacteria" group needs to be divided into two distinct groups - "True bacteria" and "Archaebacteria". This is what recent research suggests.

(A) True bacteria form a distinct evolutionary group. 
The passage suggests that true bacteria is a distinct evolutionary group.

(B) Archaebacteria are prokaryotes that resemble true bacteria.
The passage suggests this.

(C) True bacteria and eukaryotes employ similar types of genetic coding.
They have similarities.

(D) True bacteria and eukaryotes are distinguishable at the subcellular level
They are distinguishable at molecular level.

(E) Amino acid sequences of enzymes are uniform for eukaryotic and prokaryotic organisms.
Certainly incorrect.
"But even where the molecular processes are the same, the details in the two forms are different and characteristic of the respective forms. For example, the amino acid sequences of various enzymes tend to be typically prokaryotic or eukaryotic."

Answer (E)

GMATNinja · Answer

Question 7 
 
I'm not sure I fully understand your interpretation, but here are a few thoughts on (A) and (E) for question 7.

The question asks us which answer choice is NOT supported by the passage. So, if an answer choice IS supported by the passage, we can cross it out.

Here's (A):
 
As we explained in an earlier post, the passage first explains that it was "once assumed" that life could be divided into two evolutionary branches: the eukaryotic branch and "true bacteria," which are prokaryotic.

Then, the passage amends this explanation to account for three evolutionary branches: the eukaryotic branch, the true bacteria branch, and another prokaryotic branch called archaebacteria.

Even in this amended explanation, true bacteria form their own distinct evolutionary group -- the only change is that an another group is added. (A) is supported by the information in the passage, so it is not the answer to question #7.

In regards to your analysis: saying that something forms "a large coherent group" does NOT imply that there are many varieties within that group. In fact, it implies the opposite -- the definition of "coherent" is "united, or forming a whole." So, true bacteria species are united by their characteristics into a single group.

True bacteria are BOTH a distinct evolutionary group (one of the three defined in the passage), AND a coherent group.

Here's (E):
 
Remember that we are looking for an answer choice that is NOT supported by the passage. (E) tells us that, for eukaryotic and prokaryotic organisms, a certain feature is exactly the same. Is this supported by the passage?

This feature is discussed in the first paragraph:

"But even where the molecular processes are the same, the details in the two forms are  different  and characteristic of the respective forms. For example,  the amino acid sequences of various enzymes tend to be typically prokaryotic or eukaryotic. "   
This section tells us that the feature in question is  different  in eukaryotic and prokaryotic organisms. So, (E) is certainly NOT supported by the passage.

Because (E) is NOT supported by the passage, it is the correct answer to question #7.

I hope that helps!

vshr · Answer

Hello  egmat   GMATNinja ,
Why can't we say A for Q#6? As per the passage:
"although the true bacteria indeed form a large coherent group"
So, option A saying prokaryotes form a coherent group should be correct. What am I missing?
thanks!

GMATNinja · Answer

Question 6 
 
The problem with (A) is that while  true bacteria  form a large coherent group,  prokaryotes  do NOT form a large coherent group. Take a closer look at the final sentence of the second paragraph:

These techniques have strongly suggested that although the true bacteria indeed form a large coherent group, certain other bacteria, the archaebacteria, which are also prokaryotes and which resemble true bacteria, represent a distinct evolutionary branch that far antedates the common ancestor of all true bacteria.

This sentence suggests that we have two distinct groups of prokaryotes: true bacteria and archaebacteria. True bacteria may form a large coherent group, but archaebacteria (which resemble true bacteria but are different than true bacteria) are also prokaryotes. And we cannot say that all prokaryotes (true bacteria and archaebacteria) form a large coherent group. So, we can eliminate (A).

I hope that helps!

egmat · Answer

Question 7

In this EXCEPT question - you need to find the  one  statement that the passage does  NOT  support, while four others are actually mentioned or supported. Let me walk you through how to tackle this systematically.

Here's How to Approach This:

Step 1: Understand What EXCEPT Questions Ask

In EXCEPT questions, you're looking for the odd one out. Four answer choices  will  be supported by the passage, and one  won't  be. Your job is to verify each statement against what the passage actually says.

Step 2: Test Each Statement Against the Passage

Let's think about choice (E): "Amino acid sequences of enzymes are uniform for eukaryotic and prokaryotic organisms."

Notice the word  "uniform"  - this means the same across both groups, right? Now look at what the passage actually says:

"For example, the amino acid sequences of various enzymes tend to be typically prokaryotic or eukaryotic."

Here's the key insight: If something is "typically prokaryotic or eukaryotic," that means they're  characteristically different  between the two groups - the exact opposite of uniform! The passage is telling you that you can actually distinguish between prokaryotes and eukaryotes based on their amino acid sequences  because  they differ.

Step 3: Quick Verification of Other Choices

You should verify the other choices to be sure, but here's what you'll find:
 
  Choice A : The passage explicitly says "the true bacteria indeed form a large coherent group" ✓ 
  Choice B : Directly stated: "archaebacteria, which are also prokaryotes and which resemble true bacteria" ✓ 
  Choice C : The passage says they "translate genetic information into proteins according to the same type of genetic coding" ✓ 
  Choice D : The passage mentions "The distinction between eukaryotes and bacteria, initially defined in terms of subcellular structures" ✓

All of these are supported, making (E) the statement that is  NOT  supported.

Answer: E

Want to Master This Question Type?

The key to EXCEPT questions is distinguishing between what the passage actually says versus what seems plausible. The complete solution on Neuron breaks down the  progressive passage analysis technique  that helps you map exactly where each detail appears and what it means in context. You'll also see how to spot subtle word traps like "uniform" vs. "similar" that completely change the meaning. Plus, you can practice with comprehensive solutions for  other GMAT official questions on Neuron  to build your pattern recognition skills systematically.

Hope this helps! 🎯

It was once assumed that all living things could be divided into two

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GMAT Reading Comprehension (RC) Questions

It was once assumed that all living things could be divided into two

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Perfect 805 Score Debrief by Julia

My Rewards