The whole biosphere, like the individual organisms that live inside it

Question

2-1 SECTION B 25-28

The whole biosphere, like the individual organisms that live inside it, exists in a chemically dynamic state. In this homeostatic system, a great number of organic compounds are synthesized, transformed, and decomposed continuously; together, these processes constitute the major parts of the carbon cycle. For the smooth operation of this cycle, degradation is just as important as synthesis: the green plants produce great quantities of polymers, such as cellulose, and innumerable other compounds like alkaloids, terpenes, and flavonoids, that green plants cannot use as sources of energy during respiration. The release of the carbon in these compounds for recycling depends almost entirely on the action of both aerobic and anaerobic bacteria and certain types of fungi. Some bacteria and fungi possess the unique and extremely important biochemical asset of being able to catalyze the oxidation of numerous inert products, thereby initiating reaction sequences that produce carbon dioxide and so return much carbon to a form that actively enters into life cycles once again..  
 1 
 1. The passage contains information that would answer which of the following questions about the carbon cycle?

I. What are some of the compounds that are broken down in the carbon cycle?
II. Why are some compounds that are involved in the carbon cycle less reactive than others?
III. What role do bacteria and fungi play in the carbon cycle?

(A) I only
(B) II only
(C) III only
(D) I and II only
(E) I and III only

2 
 2. The author implies that which of the following is the primary reason that degradation is as important as synthesis to the smooth operation of the carbon cycle?

(A) Most of the polymers and organic compounds found in the plant kingdom are chemically unstable.
(B) The synthesis of some organic material deprives life processes of an energy source.
(C) Decomposition permits the recycling of carbon that would otherwise be fixed in certain substances.
(D) Many organisms cannot use plants as a source of food, but can feed on bacteria and fungi.
(E) Bacteria and fungi could not survive if some carbon compounds were not degraded.

3 
 3. The author’s contention about the importance of bacteria and fungi in the production of energy for life processes would be most clearly strengthened if which of the following were found to be true?

(A) Both aerobes and anaerobes provide sources of energy through the decomposition of organic material.
(B) Most compounds containing carbon are unavailable as energy sources except to some bacteria and fungi.
(C) Bacteria and fungi break down inert material in ways that do not involve oxidation.
(D) Many compounds remain inert, even in the presence of bacteria and fungi.
(E) Bacteria and fungi assist in the synthesis of many organic compounds.

Falcona · Answer

First question: 
(I) it states that there are certain types of chemical substances such as alkaloids that need to be broken down. TRUE
(II) it just says that there are some chemicals that are hard to decomposed but doesn’t say why. FALSE
(III) After stating that there are hard-to-decompose substances, it follows by clear statement that bacteria and fungi play important role in decomposing such substances. TRUE

Second question
A is not mentioned whether such substances is stable or not.
B is also not related. Question ask why decomposition is important, but B mentions why synthesis is important. 
C is clearly stated in last sentence that carbon need to be returned.
D is not mentioned at all about other organisms.
E is too broad. Even it may be true in reality, we don’t have information from the paragraph that bacteria may not survive without such substances.

Third Question
A) Apparently, it seems related but if look carefully, it talks about aerobic and anaerobes but not aerobic ‘bacteria’. False
B) It is true because it adds essential information that bacteria’s process produce energy. True
C) The paragraph says bacteria’s process involve oxidization. False
D) We don’t know that many compounds still inert or not but this is not related. We do know that some compound is not inert in the presence of bacteria. False
E) Bacteria has roles in decomposition not synthesis. False

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mimishyu · Answer

before reading this passage, it would be better if we know some important background information

1. carbon cycle: photosynthesis、decomposition、respiration、combustion
2. plants use carbon dioxide and sunlight to make their own food and grow
3. decomposers break down the dead organisms and return the carbon in their bodies to the atmosphere as carbon dioxide by respiration

Summary:

Individual organisms live inside “biosphere=homeostatic system”
------
organic compound
 “synthesize、transform、decompose”
---these processes constitute the major part of “carbon cycle”

so until this part of the passage, the author introduces the theme he intend
to discuss about--“carbon cycle”

_______________________________________________________

For smooth operation to this cycle, “degradation/decomposition” is as important as “synthesis”
 
Green plant: produce polymers&compounds
 but  plant cannot use these compounds as a source of energy during respiration

only   aerobic / anaerobic bacteria& certain types of fungi could release carbon(degradation) for recycling

----then the author further explain why those bacteria & fungi important

because it can catalyze the oxidation of numerous inert products and let carbon returns/enters into life cycle once again

1.The passage contains information that would answer which of the following questions about the carbon cycle?

I. What are some of the compounds that are broken down in the carbon cycle?

the green plants produce great quantities of polymers, such as cellulose, and innumerable other compounds like alkaloids, terpenes, and flavonoids, that green plants cannot use as sources of energy during respiration.

II. Why are some compounds that are involved in the carbon 
 cycle less reactive than others?

….not “less reactive than others”, its “totally cannot use as a 
 source of energy”

III. What role do bacteria and fungi play in the carbon cycle?
 
 Some bacteria and fungi possess the unique and extremely important biochemical asset of being able to catalyze the oxidation of numerous inert products, thereby initiating reaction sequences that produce carbon dioxide and so return much carbon to a form that actively enters into life cycles once again.

(A) I only
(B) II only
(C) III only
(D) I and II only
(E) I and III only…correct

2. The author implies that which of the following is the primary reason that degradation is as important as synthesis to the smooth operation of the carbon cycle?

(A) Most of the polymers and organic compounds found in the plant kingdom are chemically unstable.

…out of scope

(B) The synthesis of some organic material deprives life processes of an energy source.

….incorrect
although the passage says that “degradation is as important as synthesis”, the later part of the passage mainly focus on “degradation(release of carbon) force recycling” rather than synthesis, and, this is somehow a little bit hard to trace, but it indeed is a crucial point to judge whether (B) is correct or not

(C) Decomposition permits the recycling of carbon that would otherwise(in another circumstance) be fixed in certain substances.

….correct

only aerobic / anaerobic bacteria& certain types of fungi could release carbon(degradation) for recycling

----then the author further explain why the degradation of those bacteria & fungi important

because it can catalyze the oxidation of numerous inert products and let carbon returns/enters into life cycle once again

the last sentence of the whole passage is the most important idea--recycling that the author want to convey

(D) Many organisms cannot use plants as a source of food, but can feed on bacteria and fungi.

….incorrect

this idea show up in the later part of passage, but it cannot constitute a reason why degradation is as important as synthesize

(E) Bacteria and fungi could not survive if some carbon compounds were not degraded.

….incorrect
 …. “bacteria and fungi could not survive” isn’t what the passage 
 concern about, the passage only says that “these bacteria and 
 fungi could release carbon for recycling”

3. The author’s  contention about the importance of bacteria and fungi in the production of energy for life processes  would be most clearly  strengthened  if which of the following were found to be true?

(A) Both aerobes and anaerobes provide sources of energy through the decomposition of organic material.

….incorrect
This is quite tricky, its easy for us to pick up this one at first

From sentence below
 The release of the carbon in these compounds for recycling depends almost entirely on the action of both aerobic and anaerobic bacteria and certain types of fungi.

If we compare this option to (B), the difference lies upon “Both aerobes and anaerobes” and “Most compounds containing carbon”, you can notice the scope is narrower in (A) than (B), thus (B) will be a better choice
 
also for the tone in (A)&(B), (A) states in a quite affirmative way while (B) use exception to emphasize the importance of some bacteria and fungi.

(B) Most compounds containing carbon are unavailable as energy sources except to some bacteria and fungi.

….correct
The author want to put emphasize on this fact—except to some bacteria and fungi”, most compounds are unavailable as energy sources—to underline the importance of bacteria and fungi in the production of energy for life processes

(C) Bacteria and fungi break down inert material in ways that do not involve oxidation.

….out of scope

(D) Many compounds remain inert, even in the presence of bacteria and fungi.

….out of scope

(E) Bacteria and fungi assist in the synthesis of many organic compounds.

….incorrect
….though the author mention about “synthesis”, the passage doesn’t discuss about this part

For the smooth operation of this cycle, degradation is just as important as synthesis: the green plants produce great quantities of polymers, such as cellulose, and innumerable other compounds like alkaloids, terpenes, and flavonoids,  that green plants cannot use as sources of energy during respiration.  The release of the carbon in these compounds for recycling depends almost entirely on the action of both aerobic and anaerobic bacteria and certain types of fungi.  Some bacteria and fungi possess the unique and extremely important biochemical asset of being able to catalyze the oxidation of numerous inert products, thereby initiating reaction se

KarishmaB · Answer

Different exams are structured a little differently and have different expectations. So I wouldn't expect GMAT to ask whether this "What role do bacteria and fungi play in the carbon cycle?" can be answered or not. 
I know one role that some bacteria and fungi play (the release of the carbon in these compounds for recycling...) but is it the only role played? Could it be a part of a bigger role? It is unclear so I would struggle with how to answer this.

1. The passage contains information that would answer which of the following questions about the carbon cycle?

I. What are some of the compounds that are broken down in the carbon cycle?

This we can answer since we are given some compounds that are broken down. They are cellulose, alkaloids, terpenes, flavonoids... etc

II. Why are some compounds that are involved in the carbon cycle less reactive than others?

We are given that some compounds are inert but why, we don't know. Hence, we cannot answer this.

III. What role do bacteria and fungi play in the carbon cycle?

This, as I said above, I wouldn't be sure.

KarishmaB · Answer

2. The author implies that which of the following is the primary reason that degradation is as important as synthesis to the smooth operation of the carbon cycle?

(A) Most of the polymers and organic compounds found in the plant kingdom are chemically unstable.
(B) The synthesis of some organic material deprives life processes of an energy source.
(C) Decomposition permits the recycling of carbon that would otherwise be fixed in certain substances.
(D) Many organisms cannot use plants as a source of food, but can feed on bacteria and fungi.
(E) Bacteria and fungi could not survive if some carbon compounds were not degraded.

Note from the passage:
The release of the carbon in these compounds for recycling depends almost entirely on ... bacteria and fungi possess the unique and extremely important biochemical asset of being able to ... initiating reaction sequences that produce carbon dioxide and so return much carbon to a form that actively enters into life cycles once again.

Hence returning carbon to an active form (recycling of carbon) seems to be the primary reason that degradation is important.

Answer (C)

KarishmaB · Answer

3. The author’s contention about the importance of bacteria and fungi in the production of energy for life processes would be most clearly strengthened if which of the following were found to be true?

(A) Both aerobes and anaerobes provide sources of energy through the decomposition of organic material.
(B) Most compounds containing carbon are unavailable as energy sources except to some bacteria and fungi.
(C) Bacteria and fungi break down inert material in ways that do not involve oxidation.
(D) Many compounds remain inert, even in the presence of bacteria and fungi.
(E) Bacteria and fungi assist in the synthesis of many organic compounds.

First figure out what the author's contention about the importance of bacteria and fungi in the production of energy for life processes is. 
About them he says: The release of the carbon in these compounds for recycling depends almost entirely on the action of both aerobic and anaerobic bacteria and certain types of fungi...
So his contention is that they are almost entirely responsible for recycling carbon.

Then what other information will strengthen this claim?
(B) Most compounds containing carbon are unavailable as energy sources except to some bacteria and fungi.
If most compounds cannot be broken down by anyone other than some bacteria and fungi, then it makes sense that the recycling of carbon depends almost entirely on bacteria and fungi.

Answer (B)

abhola · Answer

Nice Passage. Please find my analysis of this passage below. Even though this is an official GRE passage, I am using my GMAT RC technique to solve this.

1. Read the passage for structure.
2. Identify the Main point and watch out for tone.
3. Pay attention to contrast words.
4. Okay to move on if the meaning of 1-2 sentences is not clear but the overall idea is.
5. Pay attention to the scope of the passage.
6. Understand what the question is exactly asking for.
7. Eliminate the 4 choices rather than select the right one.

Main Point - For a smooth operation of the carbon cycle, degradation is as important as synthesis. 
I think we got lucky here that the main point was kind of directly stated in the passage. Why I think this is the main point:
The first few lines introduce us to what the carbon cycle is. The next few lines after the main point describe why degradation is important and how it is generally accomplished.

Tone - Neutral

Primary Purpose - to describe important aspects of a natural phenomenon. (very abstract, but feel free to debate about it).

With this understanding, let us move on to the questions.

Q1: 1. The passage contains information that would answer which of the following questions about the carbon cycle?

1. for answer, refer to lines: "...great quantities of polymers, such as cellulose, and innumerable other compounds like alkaloids, terpenes, and flavonoids, that green..."
2. cannot be answered.
3. for answer, refer to lines: "The release of the carbon in these compounds for recycling depends almost entirely on the action of both aerobic and anaerobic bacteria and certain types of fungi."

Thus the answer is E.

Q2: The author implies that which of the following is the primary reason that degradation is as important as synthesis to the smooth operation of the carbon cycle?

For this question, I would suggest one pause and think, based on one's understanding of the passage, what the right answer could be.
My very simple response was: Because these compounds, if not recycled, will stay in plants and NOT move back into the carbon cycle.

A: At best, the opposite of this mentioned: "...able to catalyze the oxidation of numerous inert products..."
B: Could be tricky for some. It says - synthesis of some compounds DEPRIVES life process of an energy source. But its not the synthesis that does so, its the lack of ability to break these compounds down.
C: Correct, you can paraphrase from "The release of the carbon........enters into life cycles once again.."
D: Nowhere mentioned
E: Nowhere mentioned

Thus the answer is C.

Q3: The author’s contention about the importance of bacteria and fungi in the production of energy for life processes would be most clearly strengthened if which of the following were found to be true?

Strengthen the claim question

First, see what is the argument this question is asking us to refer to and strengthen.

Claim: The release of the carbon in these compounds for recycling  depends almost entirely  on the action of both aerobic and anaerobic bacteria and certain types of fungi.

Support: Some bacteria and fungi possess the unique and extremely important biochemical asset of being able to catalyze the oxidation of numerous inert products, thereby initiating reaction sequences that produce carbon dioxide and so return much carbon to a form that actively enters into life cycles once again..

Try to see why the answers are wrong not why they could be right.

A: Could be catchy. For me, it's one word off: "...decomposition of organic material." In the passage, we are talking about "intert products". We don't know whether organic material = intert products.
B: True. If only some bacteria and fungi can use carbon compounds as energy sources, then it makes sense to say "some bacteria and fungi" have the ability to take action on these carbon compounds.
C: At best, opposite of what we want
D: At best, opposite of what we want
E: This is also attractive. We are concerned about "degradation" and not "synthesis". This choice does not really address the claim as efficiently as B does.

Thus the answer is B.

Hi  Sajjad1994 , could please provide an explanation for Q3 if they are available? Thanks!

VerbalBot · Answer

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The whole biosphere, like the individual organisms that live inside it

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