Years before the advent of plate tectonics―the widely accepted theory,

The author cites Hallam on the ice ages primarily in order to
A. provide an example of a geologic phenomenon whose precise causes are not fully understood by geologists today
B. criticize the geological community for an apparent lack of consistency in its responses to new theories
C. offer evidence held to undermine a common view of why Wegener’s theory was not accepted in its day
D. give an example of a modern scientist who believes that Wegener’s theory was rejected because it failed to adequately explain the mechanical basis of continental drift
E. support Gould’s rationale for why Wegener’s theory was rejected by most geologists in the early twentieth century.

D here is a trap. D is obviously in the passage but not associated with ice age. The author uses ice age to explain that some phenomenons have been accepted without being proved 100% scientifically. So the theory that Wegner's theory was not accepted because of a lack of 100% proof is unfounded. And hence C.


Q3:The author of the passage suggests that the most likely explanation for the geological community’s response to continental drift theory in its day was that the theory
A. was in conflict with certain aspects of plate tectonics theory
B. failed to account for how mountains were formed
C. did not adequately explain how continents moved through the ocean floor
D. was contradicted by the geophysical data of the time
E. was based on a kind of evidence that was considered insufficiently convincing


From the last passage;

Wagner's theory was based on observations in contrast to tectonic plate theory which was based on scientific models and tectonic research. We can infer that the theory was rejected because the nature of evidence Wagner used was not very convincing.


Q4:It can be inferred from the passage that geologists today would be most likely to agree with which of the following statements about Wegener’s The Origin of Continents and Oceans?
A. It was a worthy scientific effort that was ahead of its time.
B. It was based on evidence that was later disproved.
C. It was directly responsible for the acceptance of the theory of plate tectonics.
D. It has been disproved by continental drift theory.
E. It misrepresented how horizontal displacements cause the formation of mountain chains.


Here the best way to go would be elimination :

A: Hmmm, yeah, it was proved to be true later, lets just hold on to it for a second.
B: Nien, it was proved to be true later. So B out.
C: Nien, the reverse is true. plate tectonics made scientists realise the veracity of Wagner
D: Straightforward nien
E: Scientists believed it then. (CLASSIC GMAT trap) Not NOW!

So from here, 4. A

In 1913 The theory was rejected.

But in 1960, a theory which overlapped Wagner's in many aspects was accepted based on proofs ( models and structures ) that we can infer, were not available during Wagner's time. Hence we can conclude that the theory was ahead of its time.

Additional question for the passage :

The author of the passage discusses the “essential presumptions” (see highlighted text) of
The Origin of Continents and Oceans most in order to
A. indicate features of Wegener's theory that caused it to be doubted in its day
B. show why Wegener's theory is now regarded as prescient
C. indicate differences between plate tectonics and the theory of continental drift
D. cite features of the theory of continental drift for which no evidence was available in
Wegener’s day
E. point out aspects of Wegener's theory that were accepted well before the advent of plate
tectonics

Answer B.

Can anyone explain answer to the last question please ?

Hi arvind910619,

Q5: The author of the passage discusses the “essential presumptions” (see highlighted text) of The Origin of Continents and Oceans most in order to

The origin of Continents and Oceans appears an impressive and prescient document, containing several of the essential presumptions underlying plate tectonics theory: the horizontal mobility of pieces of Earth's crust; the essential difference between oceanic and continental crust; and a causal connection between horizontal displacements and the formation of mountain chains. --> Wegener's theory was far ahead of its time

Yet despite the considerable overlap between Wegener's concepts and the later widely embraced plate tectonics theory, and despite the fact that continental drift theory presented a possible solution to the problem of the origin of mountains at a time when existing explanations were seriously in doubt, in its day Wegener's theory was rejected by the vast majority of geologists.

(A) indicate features of Wegener's theory that caused it to be doubted in its day -- Incorrect

(B) show why Wegener's theory is now regarded as prescient - Correct --

(C) indicate differences between plate tectonics and the theory of continental drift -- Incorrect -- it's the opposite -The origin of Continents and Oceans appears an impressive and prescient document, containing several of the essential presumptions underlying plate tectonics theory .

(D) cite features of the theory of continental drift for which no evidence was available in Wegener’s day - Incorrect

(E) point out aspects of Wegener's theory that were accepted well before the advent of platetectonics - Incorrect -- nowhere does the passage talks about parts of WT being accepted before Plate techtonics' advent

Ritwick91
passage :
Yet despite the considerable overlap between Wegener's concepts and the later widely embraced plate tectonics theory, and despite the fact that continental drift theory presented a possible solution to the problem of the origin of mountains at a time when existing explanations were seriously in doubt, in its day Wegener's theory was rejected by the vast majority of geologists.

explanation : here we are told that even though there were really important conjectures and convinving points in Wegner's theory , it was still doubted by mosy geologists

"Most geologists and many historians today believe that Wegener's theory was rejected because of its lack of an adequate mechanical basis."
- this in continuation of the last lone of 1st para : providing us the reasoning behind the doubts of most geo;losgists : inadequate mechanical basis

Stephen Jay Gould, for example, argues that continental drift theory was rejected because it did not explain how continents could move through an apparently solid oceanic floor.
- here we are given an example of a geologist who think the same as most geologist

However, as Anthony Hallam has pointed out, many scientific phenomena, such as the ice ages, have been accepted before they could be fully explained.
- "hpowever" means contrast : Hallam says we accept many scientifiv phenomena even before they are completely proved ... this implies that if geos can accept many phenomena without its complete approval why do you reject this???

POV of most geologists : lack of adequate mechanincal basis
POV of hallam : there are many scientifc things which are not adequately proved yet we accept them ... so basically the author mentions "HALLAM" to doubt the claim of most grologists

author in his next line says that : "The most likely cause for the rejection of continental drift―a cause that has been largely ignored because we consider Wegener's theory to have been validated by the theory of plate tectonics―is the nature of the evidence that was put forward to support it."

so he thinks that a plausible expkanation is something else and not what most geologists claim to be

Q1: The author cites Hallam on the ice ages primarily in order to

(A) provide an example of a geologic phenomenon whose precise causes are not fully understood by geologists today
- THIS IS AN EXPLANATION OF THE SENTENCE . IT DOES NOT TELL US "WHY THE AUTHOR HAS INTRODUCED THIS SNETECE"

(B) criticize the geological community for an apparent lack of consistency in its responses to new theories
- OPPOSITE ... we are actually told that "most geologists and hitorians" think about the same response...there is no "lack of consistency"....instead they are very much "CONSISTENT"

(C) offer evidence held to undermine a common view of why Wegener’s theory was not accepted in its day
- CORRECT ... please read explanation ... "common view" = what "most geologists" think

(D) give an example of a modern scientist who believes that Wegener’s theory was rejected because it failed to adequately explain the mechanical basis of continental drift
- OPPOSITE... this is the pirpose of "GOULD"

(E) support Gould’s rationale for why Wegener’s theory was rejected by most geologists in the early twentieth century
- OPPOSITE

4. The Progression of the last paragraph is as follows:

1.Most geologists and historians believe that Wegener's theory was rejected because there is no mechanical basis to prove his theory. Author gives an example of Gould to prove this point.
2. But in the next line, he counters this view by saying that, lack of adequate proof is not the reason because during the same time several other scientific phenomena without adequate proof were accepted and gives an example of Ice ages.

So, in short he quotes Hallam as an instance to contradict the fact that lack of adequate proof is not the real reason.

Coming to option B:
This option means that scientific community sometimes accepts new theories with no adequate proof and sometimes does not accept new theories with no adequate proof. There is no enough information in the passage for us to make such geneneralizations. Only two instances of Ice age and Continent drift are presented.

The stem for question #1 is: "The author cites Hallam on the ice ages primarily in order to..."

Let's take a look at the relevant piece of the passage:

To understand the author's intent, let's look at each piece of this section:

• The author introduces a commonly held belief (that "Wegener's theory was rejected because of its lack of an adequate mechanical basis").
• Then, he/she cites an example that contradicts this commonly held belief (Anthony Hallam's observation that people accepted phenomena such as ice ages "before they could be fully explained").
• Finally, the author offers an alternative reason for the rejection of Wegener's theory ("the nature of the evidence that was put forward to support it").

From this break down, we can see that the author cites Hallam in order to undermine a commonly held belief.

Take another look at (B):

The author definitely points out the lack of consistency in responses to new theories, but does he/she criticize the geological community for this inconsistency?

Not really -- the author is concerned with explaining why the community responded differently to different theories, but does not imply that these different responses are necessarily bad or worthy of criticism. He/she cites Hallam in order to cast doubt on a certain view, not to criticize the geologic community. For this reason, (B) is out.

I hope that helps!

geological community's consistency in decisions is not even discussed.

Geological Comunity is giving opinions on the base of evidence presents

Does any one help me explain Q2?
I don't think that "Considerable overlap" is the reason?

Before solving question 5, Let's review some Sentence Correction concepts. Note that Never had I thought how important S.C. can be by the time I encountered question 5 on this passage!

Anyway, "comma + V_ing" usually serves three functions:

1) to show "simultaneousness",
2) to delineate "immediate consequence",
3) to give "illustration" or "description" of the main event in the preciding clause.

And, Let's use this S.C. concept to find the correct answer to question 5. By the way, To understand the above-mentioned S.C. concept, Please look at an official question: https://gmatclub.com/forum/for-members- ... 48494.html

And, Ron's explanation: https://www.manhattanprep.com/gmat/foru ... tml#p95167

The relevant the excerpt from the passage:

To most geologists today, Wegener's The origin of Continents and Oceans appears an impressive and prescient document, containing several of the essential presumptions underlying plate tectonics theory:

As you see, this part uses "comma + V_ing": "... , containing...".

As in the linked S.C. question, "comma + V_ing" describes the preceding clause in the excerpt from the passage:


S.C. question: For members of the seventeenth century Ashanti nation in Africa, "animal-hide shields were essential items of military equipment, protecting warriors"

The excerpt from the passage: To most geologists today, Wegener's The origin of Continents and Oceans appears an impressive and prescient document, containing several of the essential presumptions underlying plate tectonics theory.

In S.C. quesion, " , protecting warriors" delineate HOW animal-hide shields were essential items" FOR members of Ashanti nation.

Likewise, in the passase, ",containing several of the essential presumptions underlying plate tectonics" illustrates HOW "Wegener's The origin of Continents and Oceans appears" appears an impressive and prescient document TO most geologists.


Hence, The author of the passage discusses the “essential presumptions” most in order to illustrate HOW "Wegener's The origin of Continents and Oceans" appears an impressive and prescient document.



(B) perfectly fits what we have explained.

I hope it could help!

Q2 - (D) provide a reason why it might seem surprising that continental drift theory was not more widely embraced by geologists

Where does the passage say that anyone was "surprised" that it wasn't embraced? I don't see any such indication.

Hi Vishalcv,

Please refer the below reply by expert as this addresses your issue as well:
https://gmatclub.com/forum/years-before-the-advent-of-plate-tectonics-the-widely-accepted-theory-100279.html#p2445195


Let us know if you still have doubts.
Thanks.

Hi bm2201

I did go through the explanation. I still don't see the 'surprise' factor coming in. Just because the author uses 'yet' , doesn't mean it is an indication of surprise. E looks far more suitable to me. Can you please elaborate on both the options. I have gone through all explanations on the thread, but I still don't get it. 74% of the people who have attempted the question have got it right. I just don't see what it is I am missing!

Hi Vishalcv,



Consider the lines: " Yet despite the considerable overlap between Wegener's concepts and the later widely embraced plate tectonics theory, and despite the fact that continental drift theory presented a possible solution to the problem of the origin of mountains at a time when existing explanations were seriously in doubt, in its day Wegener's theory was rejected by the vast majority of geologists."

Author refers to the "considerable overlap" between continental drift theory and plate tectonics theory as he/she ponders that even though there was an overlap between the two theories, still Wegener's theory was rejected by the vast majority of geologists in its day. The author never cites an explanation for Wegener's high standing among geologists today. He simply seems surprised or curious as to why was Wegener's not accepted then.

"Yet" here might not literally refer to being surprised, but it certainly raises the question as to what was the reason for Wegener’s being rejected back in the day and receives such recognition by geologists today. Thus D is the correct answer.


Hope This Helps.
Thanks.

In Q5 E option I thought the overall theory was rejected earlier but aspect of the theory like displacement, etc were accepted.
The overall theory was rejected because of the nature of evidence but the concepts used were not rejected earlier. Also, can you tell why B ans choice is correct

Hi nikitamaheshwari,



Now Wegner's theory is considered prescient because years before the advent of plate tectonics―the widely accepted theory, a similar theory was rejected by the geological community. In 1912, Alfred Wegener proposed, in a widely debated theory that came to be called continental drift, that Earth's continents were mobile. Thus, to most geologists today, Wegener's theory appears an impressive and prescient document.
As it was later proved that whatever Wegner had theorized was absolutely correct and accurate.

Thus B is the correct answer.


No aspect of Wegener's theory was accepted previously, as can be inferred from the lines: "Yet despite the considerable overlap between Wegener's concepts and the later widely embraced plate tectonics theory, and despite the fact that continental drift theory presented a possible solution to the problem of the origin of mountains at a time when existing explanations were seriously in doubt, in its day Wegener's theory was rejected by the vast majority of geologists." Thus E is not right.

Hope This Helps.
Thanks.