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# Although improved efficiency in converting harvested trees into wood

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Although improved efficiency in converting harvested trees into wood  [#permalink]

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Updated on: 18 Oct 2018, 05:02
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Although improved efficiency in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

(A) in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting

(B) in converting harvested trees into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and lowering prices, which boost

(C) of converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, which boosts

(D) of harvested trees being converted into wood products may reduce harvest rates, it will stimulate demand, because it will increase supply and lower prices, thereby boosting

(E) when harvested trees are converted into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and lowering prices, which boost

Originally posted by jzchina on 07 May 2006, 21:10.
Last edited by Bunuel on 18 Oct 2018, 05:02, edited 3 times in total.
Renamed the topic and edited the question.
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Although improved efficiency in converting harvested trees into wood  [#permalink]

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Updated on: 14 Aug 2019, 20:13
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Limiting to just A and B:

As an accepted custom, in two –part sentences, a pronoun first refers to the subject of the sentence and if there is no appropriate subject for the pronoun, however distantly the subject may be placed, then the given pronoun will try to stick to the nearest noun. We have to conjecture that.

In A, the subject is clearly the improved efficiency which befits the pronoun.

Now B: The subordinate clause is in active voice, while the main clause is in passive voice. How parallel is this structure?

If this exercise is from OG or GPREP, then let us take the OA. Otherwise we are entitled to contest the OA.

A is the clear choice.
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Originally posted by daagh on 04 Nov 2010, 19:43.
Last edited by daagh on 14 Aug 2019, 20:13, edited 1 time in total.
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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19 Aug 2013, 02:05
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This is GMAT Prep's OE. I hope this will help some people. I generally do not like the OEs, so I would appreciate if people can discuss about the question.
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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15 Oct 2006, 19:09
2
A seems fine.
B - "because of" seems unnecessary

C and D - IMO "of converting" somehow is less attractive than "in converting". Someone else think so too? There are other things wrong with D as well.

E - totally out.
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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15 Mar 2013, 10:41
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prasannar wrote:
Although improved efficiency in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

A. in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices,
thereby boosting.

B. In converting harvested trees into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and
lowering prices, which boost.

C. Of converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices,
which boosts.

D. Of harvested trees being converted into wood products may reduce harvest rates, it will stimulate demand, because it will increase supply
and lower prices, thereby boosting.

E. When harvested trees are converted into wood products may reduce harvest rates, demand will be stimulated because of increasing supply
and lowering prices, which boost.

Hi ishancrazee,

In this question C, D "efficiency of converting harvested trees" and "efficiency of harvested trees" are idiomatically incorrect. "When" in (E) is also not preferred because its use will imply of the efficiency at a particular time "when" harvested trees are converted into wood products.

A. in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices,
thereby boosting.

(A) correctly uses the participle "boosting" to modify the previous clause, meaning that "boosting" is a result of "increasing supply and lowering prices". Moreover "in converting" usage is better than those in other answer choices.

B. In converting harvested trees into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and
lowering prices, which boost.

In (B) if you see the last part "which boost" it means that the verb "boost" should agree with a plural subject, which in this case seems to be "increasing supply and lowering prices". On the other hand, one might say "which" modifies the noun closest to it i.e. prices; this usage will be more preferred. But, even if we take this usage into consideration, we will change the meaning of the original sentence, which intends to say that both "increasing supply and lowering prices" are boosting consumption.

C. Of converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices,
which boosts.

Incorrect as explained above

D. Of harvested trees being converted into wood products may reduce harvest rates, it will stimulate demand, because it will increase supply
and lower prices, thereby boosting.

Incorrect as explained above

E. When harvested trees are converted into wood products may reduce harvest rates, demand will be stimulated because of increasing supply
and lowering prices, which boost.

Incorrect as explained above.

Hope this helps,

Vercules
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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28 Apr 2014, 10:47
2
Miraarun12345 wrote:
Although improved efficiency in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

A. in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices,
thereby boosting.

B. In converting harvested trees into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and
lowering prices, which boost.

C. Of converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices,
which boosts.

D. Of harvested trees being converted into wood products may reduce harvest rates, it will stimulate demand, because it will increase supply
and lower prices, thereby boosting.

E. When harvested trees are converted into wood products may reduce harvest rates, demand will be stimulated because of increasing supply
and lowering prices, which boost.

I know this is found on the GMATCLUB, but a quick search gave me two different OAs A and B both. Was further confused by reading MGMAT Forum. Anyone knows what the correct OA is?

On another note, are the answers marked in GMATPREP COMPREHENSIVE SC OA reliable? TIA.

Option A) - Looks good
Although improved efficiency in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.
it replaces improved efficiency and "thereby boosting" - a verbing modifier correctly expresses the idea that act of stimulating demand by increasing supply and lowering prices will boost the consumption.

Option B) In converting harvested trees into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and
lowering prices, which boost.
which is a relative pronoun and closes noun is prices. The meaning stands as lowering prices boost consumption - Meaning changes - Incorrect.

Option C) efficiency in converting is the correct usage and which boost is the same error as B has.

Option D) efficiency in converting is the correct usage. Any segment of the sentence if it is inside the comma pair is non essential part of the sentence and can be taken out.
If we take out the non essential part of sentence, the sentence becomes as following:
it will stimulate demand, thereby boosting -> which changes the meaning. The cause and effect is removed.

Option E) Very awkward and wordy. "When harvested trees" - Incorrect.
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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29 Jun 2015, 23:15
Although improved efficiency in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

Meaning : The improved efficiency may reduce harvest rates but it will stimulate demand by increasing supply and lowering prices . The increasing supply and lowering of prices will result into boosting consumption.

So there is a cause and effect relationship between "increasing supply and lowering of prices" -> boosting consumption.

here the sentence structure of Clause + Comma + Verb+ing modifier (or participle modifier) is apt as the modifier modifies the previous clause by answering how or what resulted. Hence the usage of the modifier -> boosting is correct.

For example.
Sunita mesmerized the crowd, singing a popular song.

Now the phrase "singing a popular song" explains how "Sunita mesmerized the crowd" so the phrase "singing a popular song" modifies the previous clause.
And secondly, the action of singing attaches to the subject of the previous clause and should make sense. So in the above example, singing make sense with the subject of the previous clause "Sunita" so both the rules are satisfied for Verv+ing modifier.

So applying the same theory, the action of "boosting" attaches to the subject of the previous clause "efficiency " so the efficiency is finally boosting the consumption and that make perfect sense.

A. in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices,
thereby boosting.
As per above analysis, the option A) looks good.

B. In converting harvested trees into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and
lowering prices, which boost.

which is a relative pronoun and can refer to a noun only. Here we require a cause and effect relation where we need to modify the previous clause.

C. Of converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices,
which boosts.

which is a relative pronoun and can refer to a noun only. Here we require a cause and effect relation where we need to modify the previous clause.

D. Of harvested trees being converted into wood products may reduce harvest rates, it will stimulate demand, because it will increase supply
and lower prices, thereby boosting.

being -> is used when the action is continuous . In this example, the action of converting is not ongoing process as we make the above statement and hence the usage of "being" is wrong.
As per the original choice -> How the efficiency will stimulate demand , by increasing supply and lowering prices. But in this option the reason for stimulating demand is that efficient will increase supply and lower prices which is a meaning change (which is not required as meaning of option A is not wrong). As per option A) it seems to be a simultaneous actions, but in option D) demand will increase because of the some future action.

E. When harvested trees are converted into wood products may reduce harvest rates, demand will be stimulated because of increasing supply
and lowering prices, which boost.

When cannot be used for condition. When is used for a specific time period.
which cannot refer to the whole clause and cannot modify the whole clause.
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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10 Apr 2017, 03:06
1
Top Contributor
1
In converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices,
Before concluding that a pronoun has reference problems, we have to see whether possible contenders tally in number with the pronoun. In this case, 'it' cannot refer either to trees or products or rates, as all of them are plural and the only eligible contender is 'efficiency'. This is one of the clearest cases of pronoun reference

B, on the contrary, has a serious modifier issue. We start with a modifier" Although in converting ….' and then what is followed is not the noun that does the action of converting. It is some obscure 'demand". Therefore, B essentially suffers a misplaced modification. On top of it, the passive voice main clause makes it murkier.
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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18 Oct 2018, 04:52
aragonn GMATNinja GMATNinja2 sudarshan22 broall hazelnut Vyshak generis

Can any of the experts please take this one up?
I am stuck between A and B.
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Although improved efficiency in converting harvested trees into wood  [#permalink]

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18 Oct 2018, 15:01
5
Quote:
Although improved efficiency in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

(A) in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting

(B) in converting harvested trees into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and lowering prices, which boost

PriyankaPalit7 wrote:
generis

Can any of the experts please take this one up?
I am stuck between A and B.

PriyankaPalit7

The differences are subtle at first glance.

The A/B distinction is hard to describe with the typical code words and splits.

If I were to focus on anything in particular, it would be COMMA + WHICH
That construction creates unclear logic with missing links. Those problems lead to unclear meaning in B.

(I wish the correct answer were positioned as option E. After reading option A, a person is NOT confused. Immediately after reading A, a person reads B, which seems clear. It isn't. )

The COMMA + ___ING construction, on the other hand, creates direct, complete, and clear logic. Meaning in option A is clear.

Separating grammar and meaning in these sentences is not a great idea because ultimately meaning decides the issue.

We can, however, use noticeably different constructions in the options to tease out the meaning.

SUBJECT + BY v. NO SUBJECT + BECAUSE OF

Both by and because of are indicators of causal agency.

Stimulated (increased) demand is a result of P (increased supply) and Q (lower prices)

What causes P and Q?

Option A has an answer: improved efficiency.
The pronoun IT = improved efficiency

Improved efficiency creates an increase in supply, and that increase in supply drives down prices.
(Then lower prices create more demand, and more demand leads to more consumption.)

Option A uses one short, direct preposition and a known subject in the main clause.

In option B, P and Q are direct objects of the compound proposition "because of."

Objects of prepositions are not very active, and they certainly cannot be subjects of another clause.

This issue might not be problematic if we were dealing with a simple conjunction such as BUT.

We are not dealing with a simple construction. This question tests a different construction, namely,
Although X, Y

In option B, we do not know what causes two events. Further, no clear link TO "boost[ed] consumption" exists.

Do P and Q logically do two things?
Do P and Q cause stimulated demand (as the prepositions indicate) AND
boost consumption?

Causality is much clearer in option A than in option B because option A is not missing a link.

PARALLELISM

Option A: Although X, Y
Although improved efficiency may decrease the number of harvested trees (X), improved efficiency will [also] stimulate demand and thereby boost consumption (Y)

Option B Although X, Y in option B is
Although improved efficiency may decrease the number of harvested trees, (X), demand will be stimulated by . . . ., which boosts consumption (Y)

Despite the fact that both efficiency and demand are nouns, option B shows superficial parallelism compared to option A.
Although connotes contrast.

Option A conveys that ONE agent causes two contrasting and disparate results.
Option B conveys that ONE agent causes one result, and ANOTHER agent causes a contrasting and disparate result.

Two agents would be fine if we knew:
1) what created two agents that then created demand;
and 2) what led to a boost in consumption. That is, we have a

Problem: the second agent in B, stimulated demand, is caused by two other events, both of which seem to come out of nowhere.

Your mind may make the connection between improved efficiency and increased supply,
but option B contains no actual language from which to infer such a connection.

If we had more material, we could probably infer that more efficient conversion causes increased supply.
As the sentence stands, however, we cannot infer that improved efficiency creates increased supply.

Plausible scenario: demand for wood products stays the same whether the conversion process is more efficient or not
People do not need more wood products.

Plausible scenario: demand for wood products skyrockets because wood products that were very expensive got much cheaper because efficiency increased the supply of wood products
People DO need more wood products but could not afford those products

Two plausible but contradictory scenarios from the same fact pattern? Ambiguity. Option B is unclear.

Option A is better than Option B in the idiomatic construction Although X, Y

COMMA + ___ ING: absolutely correct. COMMA + which: almost certainly not correct.

COMMA + ---ING
In order to express the result of events or information described in a previous clause (or phrase), COMMA + ___ING is very effective and economical.

COMMA + ___ING (some people use COMMA + verbING)
-- is an adverbial modifier that uses a participle. COMMA + ____ING can modify an entire clause or phrase
-- in this instance, both thereby and boosting indicate the effect of a preceding cause:

BECAUSE improved efficiency will stimulate demand (because efficiency increases supply and thus reduces prices), improved efficiency will also increase consumption

Stripped: efficiency increases demand, thereby boosting consumption

The adverbial modifier in the form of a participial phrase is a very effective way to link one clause to subsequent events.
Correct: The tornado touched down for three minutes, destroying everything in its path.

COMMA + WHICH boost consumption
This construction is typically not very good for conveying complex causality.

If the noun or nouns that precede "which" are direct causes of whatever comes after which, the construction will usually work, but it is not as effective as a participial phrase.

COMMA + WHICH
-- is a relative clause. Almost always, COMMA WHICH must refer to an immediately preceding noun or nouns, or a noun phrase
-- boost is plural verb, indicating that the antecedent of which is plural.

This construction creates a hot mess. What is the antecedent of "which"?
Does that antecedent fit in logically?
Does THAT antecedent boost consumption?
Logically, how do we get TO the boosted consumption?

(1) If the antecedent of which is lower prices, then only lower prices boost consumption (if "which" modifies only the nearest noun).
The two other causal agents (supply and demand) in the main clause can't simply be eliminated or ignored.

(2) If the antecedent of which is the process in which increasing supply leads to lowering prices, then we lose "demand."

(3) If we allow "which" to "hop over" BOTH prepositional objects in order to reach "demand," we have a subject/verb error.

In (1), we cannot simply eliminate those other two causal agents (supply and demand); lower prices are part of a causal chain that includes those two agents.

In (2), we cannot simply eliminate "demand."
-- Demand is the result of greater supply and lower prices
-- Stimulated demand MAY be the direct cause of boosted consumption. (see the logical chain below).

This question is hard.

Option A is far better than Option B.

I hope that analysis helps. (Whew!)

I have separated causality from grammar cues in an artificial way because it is really difficult to explain the chain of events, the logical sequence.
The meaning of the sentence is tied directly to that sequence.
We have nested agents of change (the "Russian doll" scenario).

The logical line of causation is direct.
The words and phrasing do not seem to be direct.

MEANING depends on CLARITY and COMPLETENESS of logic
If you can analyze the meaning of the two sentences, the correct answer becomes obvious.

The sentence means that
-- more efficient conversion of trees to wood products may
reduce the number of trees that must be chopped down,
but
the improved efficiency will lead to
an increase in supply, which leads to
a decrease in price, which leads to
an increase in demand, which finally leads to
an increase in consumption.

Overall meaning: Although improved efficiency may lead to a Good Thing, improved efficiency [also] will lead to a Bad Thing.

CAUSALITY

The final outcome is boosted (increased) consumption
That outcome tacitly leads companies to chop down more trees, a result that nullifies the saving of trees created by improved efficiency.

What directly causes increased consumption?
Option A: Stimulated demand.
Option B: unclear

-- Reduced prices do not cause increased consumption.
-- Increased supply does not cause increased consumption.
-- Those two events create greater demand.

More accurately, increased supply results in reduced prices, and reduced prices result in stimulated demand.

For example, reduced prices would not cause an increase in supply. Greater supply comes first.
Think about the matter from a profiteer's perspective.
Why would I produce MORE wood products in a market in which I get paid LESS for them?

We do not have to be economists. The logic of the prepositions by and because of is
EFFECT (demand) by CAUSE (greater supply that leads to lower prices)
EFFECT (demand) because of CAUSE (greater supply that leads to lower prices)

We cannot jump from improved efficiency to stimulated demand (higher demand). Other causal agents intervene.

Option A contains this causal sequence:
Improved efficiency → increased supply → reduced prices → stimulated (higher) demand → boosted (higher) consumption

Improved efficiency (1) increases supply (2).
Increased supply (2) decreases prices (3).
Lower prices (3) stimulate demand (4).
Higher demand (4) boosts (increases) consumption (5).

In option A
The word order in the causal sequence of the main clause is 1 → 4 → 2→ 3, →5
The logical order 1→2→3→4→5, however, is intact.
The meaning of the sentence is also intact.
Although improved efficiency may reduce rates (X), improved efficiency will also stimulate demand by __ and ___, increasing consumption (Y)

Option B contains this causal sequence:
Increasing supply (1) causes a lowering of prices. (2)
Lower prices (2) create stimulated demand. (3)
SOMETHING unclear causes boosted consumption (4)

The word order in the main clause is 3 → 1→2,[??] →4
The logical order is not intact.
The meaning of the sentence has changed.
Although improved efficiency may reduce rates (X), demand will be stimulated by __ and __, and something will boost consumption. (Y)

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Although improved efficiency in converting harvested trees into wood  [#permalink]

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18 Oct 2018, 15:49
1
Awesome analysis generis

I have one small additional query.
If coma+verb-ing modifier presents the results of a preceding clause,
is not thereby redundant in (A) ?

I would place much more emphasis on parallelism issue than
a. voice (active/ passive) as pointed out
by daagh above (contrast is much more clear with a single subject: improved efficiency)
b. Usage of coma+ verb-ing modifier vs logical antecedent of which, although
plural verb boost did help me to know I am referring to plural nouns.

I always have nightmares with usage of that/ which and use below rule:
• When that/which is used as a relative pronoun, it can refer only to the singular noun
• When that/which is used as a noun modifier, it can refer to singular/ plural nouns.

Whenever in doubt, I can use the verb that follows that / which as you did in above and then
look into meaning/ casuality (aptly conveyed by coma+verb-ing modifier) in the sentence.
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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01 Sep 2019, 04:59
EducationAisle

In option A, doesn't "thereby reducing" modify the subject of the sentence "it" which refers to "improved efficiency" and its verb? However the "thereby reducing" should modify "increasing supply and lowering prices". Please respond to this question in detail since I am confused and it seems I have some knowledge gap regarding comma + verb-ing modifiers

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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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01 Sep 2019, 05:08
1
Brego7 wrote:
In option A, doesn't "thereby reducing" modify the subject of the sentence "it" which refers to "improved efficiency" and its verb

Well, thereby reducing will indeed modify the subject of the sentence it, which refers to improved efficiency (not sure what you mean by and its verb; a pronoun cannot refer to a verb; by its very definition, a pronoun can only refer to a noun/noun-phrase).

Brego7 wrote:
However the "thereby reducing" should modify "increasing supply and lowering prices".

Well, a case can definitely be made that improved efficiency boosts consumption (by increasing supply and lowering prices). So, this is in fact a very classical use of present perfect.
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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28 Sep 2019, 06:11
generis wrote:
Quote:
Although improved efficiency in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

(A) in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting

(B) in converting harvested trees into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and lowering prices, which boost

PriyankaPalit7 wrote:
generis

Can any of the experts please take this one up?
I am stuck between A and B.

PriyankaPalit7

The differences are subtle at first glance.

The A/B distinction is hard to describe with the typical code words and splits.

If I were to focus on anything in particular, it would be COMMA + WHICH
That construction creates unclear logic with missing links. Those problems lead to unclear meaning in B.

(I wish the correct answer were positioned as option E. After reading option A, a person is NOT confused. Immediately after reading A, a person reads B, which seems clear. It isn't. )

The COMMA + ___ING construction, on the other hand, creates direct, complete, and clear logic. Meaning in option A is clear.

Separating grammar and meaning in these sentences is not a great idea because ultimately meaning decides the issue.

We can, however, use noticeably different constructions in the options to tease out the meaning.

SUBJECT + BY v. NO SUBJECT + BECAUSE OF

Both by and because of are indicators of causal agency.

Stimulated (increased) demand is a result of P (increased supply) and Q (lower prices)

What causes P and Q?

Option A has an answer: improved efficiency.
The pronoun IT = improved efficiency

Improved efficiency creates an increase in supply, and that increase in supply drives down prices.
(Then lower prices create more demand, and more demand leads to more consumption.)

Option A uses one short, direct preposition and a known subject in the main clause.

In option B, P and Q are direct objects of the compound proposition "because of."

Objects of prepositions are not very active, and they certainly cannot be subjects of another clause.

This issue might not be problematic if we were dealing with a simple conjunction such as BUT.

We are not dealing with a simple construction. This question tests a different construction, namely,
Although X, Y

In option B, we do not know what causes two events. Further, no clear link TO "boost[ed] consumption" exists.

Do P and Q logically do two things?
Do P and Q cause stimulated demand (as the prepositions indicate) AND
boost consumption?

Causality is much clearer in option A than in option B because option A is not missing a link.

PARALLELISM

Option A: Although X, Y
Although improved efficiency may decrease the number of harvested trees (X), improved efficiency will [also] stimulate demand and thereby boost consumption (Y)

Option B Although X, Y in option B is
Although improved efficiency may decrease the number of harvested trees, (X), demand will be stimulated by . . . ., which boosts consumption (Y)

Despite the fact that both efficiency and demand are nouns, option B shows superficial parallelism compared to option A.
Although connotes contrast.

Option A conveys that ONE agent causes two contrasting and disparate results.
Option B conveys that ONE agent causes one result, and ANOTHER agent causes a contrasting and disparate result.

Two agents would be fine if we knew:
1) what created two agents that then created demand;
and 2) what led to a boost in consumption. That is, we have a

Problem: the second agent in B, stimulated demand, is caused by two other events, both of which seem to come out of nowhere.

Your mind may make the connection between improved efficiency and increased supply,
but option B contains no actual language from which to infer such a connection.

If we had more material, we could probably infer that more efficient conversion causes increased supply.
As the sentence stands, however, we cannot infer that improved efficiency creates increased supply.

Plausible scenario: demand for wood products stays the same whether the conversion process is more efficient or not
People do not need more wood products.

Plausible scenario: demand for wood products skyrockets because wood products that were very expensive got much cheaper because efficiency increased the supply of wood products
People DO need more wood products but could not afford those products

Two plausible but contradictory scenarios from the same fact pattern? Ambiguity. Option B is unclear.

Option A is better than Option B in the idiomatic construction Although X, Y

COMMA + ___ ING: absolutely correct. COMMA + which: almost certainly not correct.

COMMA + ---ING
In order to express the result of events or information described in a previous clause (or phrase), COMMA + ___ING is very effective and economical.

COMMA + ___ING (some people use COMMA + verbING)
-- is an adverbial modifier that uses a participle. COMMA + ____ING can modify an entire clause or phrase
-- in this instance, both thereby and boosting indicate the effect of a preceding cause:

BECAUSE improved efficiency will stimulate demand (because efficiency increases supply and thus reduces prices), improved efficiency will also increase consumption

Stripped: efficiency increases demand, thereby boosting consumption

The adverbial modifier in the form of a participial phrase is a very effective way to link one clause to subsequent events.
Correct: The tornado touched down for three minutes, destroying everything in its path.

COMMA + WHICH boost consumption
This construction is typically not very good for conveying complex causality.

If the noun or nouns that precede "which" are direct causes of whatever comes after which, the construction will usually work, but it is not as effective as a participial phrase.

COMMA + WHICH
-- is a relative clause. Almost always, COMMA WHICH must refer to an immediately preceding noun or nouns, or a noun phrase
-- boost is plural verb, indicating that the antecedent of which is plural.

This construction creates a hot mess. What is the antecedent of "which"?
Does that antecedent fit in logically?
Does THAT antecedent boost consumption?
Logically, how do we get TO the boosted consumption?

(1) If the antecedent of which is lower prices, then only lower prices boost consumption (if "which" modifies only the nearest noun).
The two other causal agents (supply and demand) in the main clause can't simply be eliminated or ignored.

(2) If the antecedent of which is the process in which increasing supply leads to lowering prices, then we lose "demand."

(3) If we allow "which" to "hop over" BOTH prepositional objects in order to reach "demand," we have a subject/verb error.

In (1), we cannot simply eliminate those other two causal agents (supply and demand); lower prices are part of a causal chain that includes those two agents.

In (2), we cannot simply eliminate "demand."
-- Demand is the result of greater supply and lower prices
-- Stimulated demand MAY be the direct cause of boosted consumption. (see the logical chain below).

This question is hard.

Option A is far better than Option B.

I hope that analysis helps. (Whew!)

I have separated causality from grammar cues in an artificial way because it is really difficult to explain the chain of events, the logical sequence.
The meaning of the sentence is tied directly to that sequence.
We have nested agents of change (the "Russian doll" scenario).

The logical line of causation is direct.
The words and phrasing do not seem to be direct.

MEANING depends on CLARITY and COMPLETENESS of logic
If you can analyze the meaning of the two sentences, the correct answer becomes obvious.

The sentence means that
-- more efficient conversion of trees to wood products may
reduce the number of trees that must be chopped down,
but
the improved efficiency will lead to
an increase in supply, which leads to
a decrease in price, which leads to
an increase in demand, which finally leads to
an increase in consumption.

Overall meaning: Although improved efficiency may lead to a Good Thing, improved efficiency [also] will lead to a Bad Thing.

CAUSALITY

The final outcome is boosted (increased) consumption
That outcome tacitly leads companies to chop down more trees, a result that nullifies the saving of trees created by improved efficiency.

What directly causes increased consumption?
Option A: Stimulated demand.
Option B: unclear

-- Reduced prices do not cause increased consumption.
-- Increased supply does not cause increased consumption.
-- Those two events create greater demand.

More accurately, increased supply results in reduced prices, and reduced prices result in stimulated demand.

For example, reduced prices would not cause an increase in supply. Greater supply comes first.
Think about the matter from a profiteer's perspective.
Why would I produce MORE wood products in a market in which I get paid LESS for them?

We do not have to be economists. The logic of the prepositions by and because of is
EFFECT (demand) by CAUSE (greater supply that leads to lower prices)
EFFECT (demand) because of CAUSE (greater supply that leads to lower prices)

We cannot jump from improved efficiency to stimulated demand (higher demand). Other causal agents intervene.

Option A contains this causal sequence:
Improved efficiency → increased supply → reduced prices → stimulated (higher) demand → boosted (higher) consumption

Improved efficiency (1) increases supply (2).
Increased supply (2) decreases prices (3).
Lower prices (3) stimulate demand (4).
Higher demand (4) boosts (increases) consumption (5).

In option A
The word order in the causal sequence of the main clause is 1 → 4 → 2→ 3, →5
The logical order 1→2→3→4→5, however, is intact.
The meaning of the sentence is also intact.
Although improved efficiency may reduce rates (X), improved efficiency will also stimulate demand by __ and ___, increasing consumption (Y)

Option B contains this causal sequence:
Increasing supply (1) causes a lowering of prices. (2)
Lower prices (2) create stimulated demand. (3)
SOMETHING unclear causes boosted consumption (4)

The word order in the main clause is 3 → 1→2,[??] →4
The logical order is not intact.
The meaning of the sentence has changed.
Although improved efficiency may reduce rates (X), demand will be stimulated by __ and __, and something will boost consumption. (Y)

generis

need your help, in option A, is the two IC cluase are not joined just through a "," only?

Is this example is a run-on sentence?
could you please help me identifying this type of error, if some specific rules are there to spot?
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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29 Apr 2020, 01:12
jzchina wrote:
Although improved efficiency in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

(A) in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting

(B) in converting harvested trees into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and lowering prices, which boost

(C) of converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, which boosts

(D) of harvested trees being converted into wood products may reduce harvest rates, it will stimulate demand, because it will increase supply and lower prices, thereby boosting

(E) when harvested trees are converted into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and lowering prices, which boost

The answer has to be between A or B. Obviously C,D,E do not make much sense.

Let's analyse:

First error: 'it', gmat doesn't support use of the word 'it' because in most cases it causes ambiguity in what we are referring to. 'It' could refer to the 'Improved efficiency' or 'harvest rates'. So the use of 'it' is redundant.

If we are to talk about the process as a whole Option B would be the choice. Here many would argue the word 'Boost' not being parallel as in A. However, Boosting may not be parallel to 'increasing' and 'lowering' as they belong to a different list altogether. 'Boost' should hence be parallel to 'Demand'.
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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29 Apr 2020, 03:23
xcxsaffi wrote:
jzchina wrote:
Although improved efficiency in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

(A) in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting

(B) in converting harvested trees into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and lowering prices, which boost

(C) of converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, which boosts

(D) of harvested trees being converted into wood products may reduce harvest rates, it will stimulate demand, because it will increase supply and lower prices, thereby boosting

(E) when harvested trees are converted into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and lowering prices, which boost

The answer has to be between A or B. Obviously C,D,E do not make much sense.

Let's analyse:

First error: 'it', gmat doesn't support use of the word 'it' because in most cases it causes ambiguity in what we are referring to. 'It' could refer to the 'Improved efficiency' or 'harvest rates'. So the use of 'it' is redundant.

If we are to talk about the process as a whole Option B would be the choice. Here many would argue the word 'Boost' not being parallel as in A. However, Boosting may not be parallel to 'increasing' and 'lowering' as they belong to a different list altogether. 'Boost' should hence be parallel to 'Demand'.

Hey there
It seems that your analysis is incorrect.

It is nowhere mentioned that GMAT does not support the use of the pronoun 'it'. In fact, there are many official questions that use this pronoun. Also, the correct answer is A. Lets see how

Although improved efficiency in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

MEANING
The sentence says that because the efficiency in converting the harvested trees into the final wooden products has improved, this improvement in efficiency may reduce the harvest rates. Now contrasting this outcome with another anticipated outcome the author says that because the efficiency is improved it will increase the demand of wood products by increasing the supply and reducing the prices. Because of these factors, consumption will boost. Therefore the sentence is trying to present a cause and relationship between the change in factors because of increased efficiency and the boost in consumption.

A. in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting.
In this choice 'it' clearly refers to improved efficiency. There is no pronoun ambiguity here. All the lists are parallel and this choice conveys the logical meaning clearly as described above

B. in converting harvested trees into wood products may reduce harvest rates, demand will be stimulated because of increasing supply and lowering prices, which boost
This choice has changed the intended meaning. The demand is getting increased because of increasing supply and lowering prices, but there is no connection between how the supply is increased and prices decreased. The usage of 'which boost' fails to show the cause and relation as explained in the meaning.
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I hope this helps.
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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29 Apr 2020, 03:42
Hey there J2S2019

Lets first look at the definitions of dependant and independent clauses
IC: An independent clause is a set of words that contains a subject and a verb and expresses a complete thought. It is a stand-alone clause.
eg 1 Many teenagers undergo stress.

DC: A dependent clause is a set of words that contains a subject and a verb but does not express a complete thought. It is not a stand-alone clause.
eg 2 While many teenagers undergo stress,

In eg 1 it is a complete sentence and has a complete meaning whereas in eg 2 the meaning is incomplete. DC cannot be called a sentence.

A dependent clause can be identified by a dependent marker such as although, as, because, even though, since, though, unless, while, etc

Although improved efficiency in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

Red: DC; Blue: IC
Whenever DC comes before IC they can be connected by ',' comma. Hence the structure of the sentence is correct.

When there are two IC you need conjunction such as and, but, so, or etc between them
eg Samuel is a good boy and he comes first in the class.
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I hope this helps.
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Anmol
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Re: Although improved efficiency in converting harvested trees into wood  [#permalink]

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14 May 2020, 00:33
comma+which clause shows a characteristics of of the preceding noun because it is non-restrictive. that-clause specify which kind of preceding noun among many nouns because it is restrictive.

so, in choice B, "which clause" modifies "increasing supplies and lowering prices" , showing characteristics of "supplies and prices". this is not logical because the "supplies and prices" do not this characteristic of boosting

gmat test whether the change from which-clause to adverbial phrase is logical. this point is tested many times.
Re: Although improved efficiency in converting harvested trees into wood   [#permalink] 14 May 2020, 00:33