For years scientists have argued about what exactly caused the extinct

Question

For years scientists have argued about what exactly caused the extinction of the dinosaurs. A key to this question is dinosaur physiology. One topic of hot debate among paleontologists is thermoregulation or control of body temperature. All animals exhibit some form of thermoregulation through migration, perspiration, shivering, or hibernation; yet they fall into two distinct groups. Ectothermy is a form of thermoregulation, which requires that the animal regulate its temperature through behavior and autonomic, external environment. Reptiles and amphibians are ectotherms, which mean they gain heat from an outside energy source. They require little food, as their metabolic rate is low, however, ectotherms cannot withstand extreme cold. On the other hand, mammals and birds, are endothermic. They have a tachymetabolic (high-speed) metabolism, which produces body heat internally.

Endothermy is a highly effective but expensive state, as the elevated metabolic rate requires a high caloric intake each day. Because dinosaurs are extinct, their physiology cannot be measured by usual scientific method (temperature measurement, record of food consumption, and output of carbon dioxide and solid waste). Fossils initially indicated to early scientists that dinosaurs were ectotherms, because of their external physical similarity to modern-day reptiles (jawbones, scales, etc.). However, in recent years, scientists have reversed their preliminary findings as modern indirect evidence seems to suggest that dinosaurs were endotherms.

The debate is still open. Two dinosaur clans were herbivores with such developed an intricate dental equipment that scientists assume they must have been tachymetabolic, or endothermic. However, other dinosaurs lack those evolutions. Bipedal dinosaurs are thought to have been very fleet, suggesting endothermic behavior. Also leading scientists to that conclusion were the talons on their feet; balancing must have required a high degree of agility and activity consistent with endothermic behavior. Another compelling form of evidence is the fact that most dinosaurs stood upright, which means that their hearts had to be sophisticated and powerful enough to pump blood to their elevated brains. Scientists believe that dinosaurs had to possess the double-pump heart found in other endotherms. However, the fossil record is incomplete; scientists are basing their assumptions on partial evidence.

Scientists can draw no definitive conclusions. Just because dinosaurs had the ability to be endothermic, doesn't mean they were, at least, not exclusively. Modern technology has made possible the operation of cars, houses, appliances, etc. by solar energy; still, society has not given up its use of electricity, gas and oil. Current speculation among scientists places dinosaurs somewhere in between both extremes, a hypothesis which could lead to a new chapter in the story of evolutionary theory.     1 
 1. This passage was most likely excerpted from:

A. a paleontologist's science journal
B. an article on the methods involved in the study of fossils
C. a researcher's guide to the importance of not drawing conclusions from insufficient evidence
D. a summary of the debate surrounding dinosaurs' thermoregulation system 
E. an explanation of the new advances in the theory of evolution

2 
 2. The main idea of the passage is:

A. to open a new direction for evolutionary study
B. to demonstrate that there is no clear answer to the question of dinosaur physiology 
C. to suggest that there are large gaps in the fossil record
D. to examine the reasons that dinosaurs are extinct
E. to prove that dinosaurs are endothermic

3 
 3. According to the information in the passage, scientists base their theories on the thermoregulation of dinosaurs on:

A. conventional methods of inquiry into physiology
B. detailed investigations of dinosaur genetics
C. examination of records of consumption, waste and temperature fluctuation
D. advances in the area of physiological research
E. investigation of fossilized remains

GMAT Club's Reading Comprehension (RC) Quiz-I 2023   
   10 Days | 20 Passages | Win Prizes | Get Better at GMAT   
 Passage # 02  |  Date: 01 March 2023 
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$!vakumar.m · Answer

1. This passage was most likely excerpted from:

A. a paleontologist's science journal -  paleontologists study ancient life through fossils as its main source - but the passage focusses more on other modern indirect evidence obtained from study of physiology as highlighted in the third paragraph. Incorrect

B. an article on the methods involved in the study of fossils -  as explained above - Incorrect

C. a researcher's guide to the importance of not drawing conclusions from insufficient evidence -  though mentioned in third paragraph, this option seems to be a trap. The focus of the passage is on the discussion of whether the dinosaurs were ectothermic or endothermic. Incorrect.

D. a summary of the debate surrounding dinosaurs' thermoregulation system -  Correct. The whole passage is dedicated to the debate on determining whether the dinosaurs were ectothermic or endothermic - to identify the exact cause of their extinction.

E. an explanation of the new advances in the theory of evolution -  the new advances in the theory of evolution is mentioned only in the last paragraph of the passage- Incorrect

Answer D

2. The main idea of the passage is:

As discussed above, the focus of the passage is to determine the dinosaurs' thermoregulation system - ectothermic or endothermic, in order to identify the exact cause of their extinction.

A. to open a new direction for evolutionary study -  the author mentions that the dinosaurs may be placed somewhere in between both extremes of ectotherms or endotherms and  he indicates  that this hypothesis  could lead  to a new chapter in the story of evolutionary theory - Incorrect.

B. to demonstrate that there is no clear answer to the question of dinosaur physiology -  seems correct. The author discusses that scientists - based on their study of Fossils - initially indicated that dinosaurs were ectotherms, however, they have now reversed their preliminary findings as modern indirect evidence seems to suggest that dinosaurs were endotherms. But, the debate is still open as they are not in a position to draw definitive conclusions from the available evidence.

C. to suggest that there are large gaps in the fossil record - this option is narrow in scope -  though it is mentioned that the fossil records are insufficient to determine the dinosaurs physiology, but it is just one part of the ongoing debate - Incorrect

D. to examine the reasons that dinosaurs are extinct - this aim is mentioned in the first paragraph -  however, the passage focusses on the debate of whether the dinosaurs were ectothermic or endothermic, and discusses the lack of sufficient/conclusive evidence to determine the same - Incorrect

E. to prove that dinosaurs are endothermic -  this is a strong statement, as the author mentions that the debate is ongoing and scientists can draw no definitive conclusions. - Incorrect.

Oppenheimer1945 · Answer

2. The main idea of the passage is:

A. to open a new direction for evolutionary study  (it's only mentioned in the last part of passage)

B. to demonstrate that there is no clear answer to the question of dinosaur physiology  (no demonstration done by author)

C. to suggest that there are large gaps in the fossil record  ( true )

D. to examine the reasons that dinosaurs are extinct  (reasons for extinction is not examined by author)

E. to prove that dinosaurs are endothermic  (proving dinasaurs as endothermic)

3. According to the information in the passage, scientists base their theories on the thermoregulation of dinosaurs on:

A. conventional methods of inquiry into physiology  (not true)

B. detailed investigations of dinosaur genetics  (genetics not mentioned in passage)

C. examination of records of consumption, waste and temperature fluctuation  (it's opposite of what's given in passage)

D. advances in the area of physiological research  (advances in area is not mentioned)

E. investigation of fossilized remains  (true) -  Ectothermy is a form of thermoregulation, which requires that the animal regulate its temperature through behavior and autonomic, external environment. Reptiles and amphibians are ectotherms, Fossils initially indicated to early scientists that dinosaurs were ectotherms,

limuengaoey · Answer

Q3. E as fossils classified dinosaurs into 2 groups

Catman · Answer

Passage 1: Dinosaurs extinction's reason can be answered by dinosaur physiology.Two groups based on temp. regulations : Ectotherms (Gain heat from external), endotherm (gain heat from internal)

Passage 2: Early scientist believe Dinosaurs to be ectotherms (as they are physically similar to reptiles), but based on modern indirect evidence they reversed thier findings and suggested Dinosaurs are endotherms.

Passage 3: No clarity about whether dinosaurs are endotherms or ectotherms as their Fossil record is incomplete and scientist are assuming based on partial evidence.

Passage 4: Current no clarity on whether dinosaurs are endotherm or ectotherms, scientist place dinosaurs somewhere in between both extremes.

1. This passage was most likely excerpted from:

A. a paleontologist's science journal ~  Incorrect, the language of the passage is used is not of a science journal.

B. an article on the methods involved in the study of fossils ~  Incorrect passage is not about the method involved in the study of fossils

C. a researcher's guide to the importance of not drawing conclusions from insufficient evidence ~  Incorrect passage is not a guide and not suggest to drawing any conclusions from insufficient evidence.

D. a summary of the debate surrounding dinosaurs' thermoregulation system ~  Correct author presents a debate whether dinosaurs are endotherms or ectotherms

E. an explanation of the new advances in the theory of evolution ~ Incorrect no thoery of evaluation is explained in the passage.

The main idea of the passage is:

A. to open a new direction for evolutionary study ~  Incorect, author states that "hypothesis will open a new direction" but no supporting evidence that authors wants to open new direction.

B. to demonstrate that there is no clear answer to the question of dinosaur physiology ~  Correct author is presenting that it can't be clearly defined that whether dinosaurs are endotherms or exotherms and Scientists can draw no definitive conclusion  .

C. to suggest that there are large gaps in the fossil record ~  Incorrect author agrees that there are large gaps but this is a partial idea not main idea.

D. to examine the reasons that dinosaurs are extinct ~  InCorrect, author does not examines the reasons why dinasours are extinct, author highlight only one reason i:e control of body temperature and based on this wants to finds out whether dinosaurs are exotherm or endotherm.

E. to prove that dinosaurs are endothermic ~  Incorrect "Just because dinosaurs had the ability to be endothermic, doesn't mean they were, at least, not exclusively" author is not proving that dinosaurs are endothermic.

According to the information in the passage, scientists base their theories on the thermoregulation of dinosaurs on:

A. conventional methods of inquiry into physiology ~  Incorrect as per the passage "Because dinosaurs are extinct, their physiology cannot be measured by usual scientific method"

B. detailed investigations of dinosaur genetics ~  Incorrect No mention of dinosaur genetics in the passage

C. examination of records of consumption, waste and temperature fluctuation ~  Incorrect, it is mentioned that "their physiology cannot be measured by usual scientific method (temperature measurement, record of food consumption, and output of carbon dioxide and solid waste)"

D. advances in the area of physiological research ~ Incorrect the classification is based on the basis of available fossil record"

E. investigation of fossilized remains ~  Correct- as "However, the fossil record is incomplete; scientists are basing their assumptions on partial evidence." On the basis of fossil they are classifying dinosaurs as endotherms or ectotherms.

1. D 2. B 3. E

Elite097 · Answer

1. This passage was most likely excerpted from:

A. a paleontologist's science journal----  if this was a debate among paleontologistss, this would not be mentioned : "One topic of hot debate among paleontologists is thermoregulation or control of body temperature"

B. an article on the methods involved in the study of fossils---  no methods discussed

C. a researcher's guide to the importance of not drawing conclusions from insufficient evidence---  not researcher perspective

D. a summary of the debate surrounding dinosaurs' thermoregulation system--  yes cuz it presents the debate

E. an explanation of the new advances in the theory of evolution--  no advances made

Ans D

2.The main idea of the passage is:

A. to open a new direction for evolutionary study---  not purpose 
B. to demonstrate that there is no clear answer to the question of dinosaur physiology-  yes 
C. to suggest that there are large gaps in the fossil record--  not the purpose 
D. to examine the reasons that dinosaurs are extinct--  only 1 reason is there - physiology 
E. to prove that dinosaurs are endothermic--  no proof

Ans B

3. According to the information in the passage, scientists base their theories on the thermoregulation of dinosaurs on:

A. conventional methods of inquiry into physiology--  no 
B. detailed investigations of dinosaur genetics--  not mentioned 
C. examination of records of consumption, waste and temperature fluctuation--  clearly mentioned its not used 
D. advances in the area of physiological research--  no advances made 
E. investigation of fossilized remains--  yes

Ans E

0Lucky0 · Answer

Q1. This passage was most likely excerpted from:

A. a paleontologist's science journal
B. an article on the methods involved in the study of fossils
C. a researcher's guide to the importance of not drawing conclusions from insufficient evidence
 D. a summary of the debate surrounding dinosaurs' thermoregulation system  
E. an explanation of the new advances in the theory of evolution

Q2. The main idea of the passage is:

A. to open a new direction for evolutionary study
 B. to demonstrate that there is no clear answer to the question of dinosaur physiology  
C. to suggest that there are large gaps in the fossil record
D. to examine the reasons that dinosaurs are extinct
E. to prove that dinosaurs are endothermic

Sajjad1994 · Answer

OAs are revealed now

DBE

Competition mode is off now

Excellent  sivakumarm786  8/10
 Catman  7/10
 Elite097  5/10
Once again hard luck  samagra21

Keep participating in this quiz I hope your RC preparation will improve. Also please format your replies, it will help the new comer members on the post.

Let me know your thoughts (If any)

Best of luck on the upcoming questions.

Elite097 · Answer

Sajjad1994  this scoring is suer arbitrary tbh. If this is so its going to be super discouraging for participation

carcass · Answer

Please sir, fix the typos or write without abbreviations

tbh= ????

Also, what is in the scoring "arbitrary" in your view??

We are here to be unbiased as much as possible

regards

Sajjad1994 · Answer

Hello  sivakumarm786 
 samagra21 
 Catman 
 Elite097 
 0Lucky0

Formatted your replies on this one too. Please follow the format to make things easier.

Sajjad1994 · Answer

Hello Elite097

I have no mean to discourage anyone at all and the evaluation is justified according to my best limited knowledge

All the explanations will be marked or evaluated based on the three factors.

1.  Accuracy
 2.  Logical connection of explanations
 3.  Efforts put in to write up the explanation

So this is a test of your GMAT Reading comprehension accuracy + Logical thinking (whether one has got the question correct for the right reason) + Stemna to write down the explanation.

Sajjad1994 · Answer

Explanation

1. This passage was most likely excerpted from:

Explanation

The passage is mainly about the debate surrounding the thermoregulation system of dinosaurs, and the evidence supporting both ectothermy and endothermy. The correct answer is  D , a summary of the debate surrounding dinosaurs' thermoregulation system.

Option A , a paleontologist's science journal, could be a possible choice, but the passage is not written in a technical or academic style. It is more of a general overview and does not focus on any particular study or experiment.

Option B , an article on the methods involved in the study of fossils, is incorrect because the passage briefly mentions fossils, but it is not the main focus.

Option C , a researcher's guide to the importance of not drawing conclusions from insufficient evidence, is incorrect because while the passage does mention the incomplete nature of the fossil record and the need to avoid premature conclusions, it is not the primary message.

Option E , an explanation of the new advances in the theory of evolution, is incorrect because the passage does not mention any new advances in the theory of evolution, and the discussion is limited to the thermoregulation of dinosaurs.

Therefore, the correct answer is  D , a summary of the debate surrounding dinosaurs' thermoregulation system.

Answer: D

Sajjad1994 · Answer

Explanation

2. The main idea of the passage is:

Explanation

The main idea of the passage is to demonstrate that there is no clear answer to the question of dinosaur physiology. The passage discusses the debate among scientists regarding whether dinosaurs were ectothermic or endothermic and presents evidence for both sides of the argument. While some evidence suggests that dinosaurs were endothermic, the author makes it clear that there is no definitive conclusion and that scientists are still basing their assumptions on partial evidence. Therefore, option  B  is the correct answer.

Option A  is incorrect because while the passage discusses the possibility of a new chapter in evolutionary theory, it does not suggest that this is the main idea of the passage.

Option C  is also incorrect because while the passage acknowledges gaps in the fossil record, it does not suggest that this is the main idea.

Option D  is incorrect because while the passage briefly mentions the extinction of the dinosaurs, it does not examine the reasons for their extinction in detail.

Option E  is incorrect because while the passage discusses the possibility that dinosaurs were endothermic, it also presents evidence for the opposing argument and makes it clear that there is no definitive conclusion.

Answer: B

Sajjad1994 · Answer

Explanation

3. According to the information in the passage, scientists base their theories on the thermoregulation of dinosaurs on:

Explanation

The passage clearly states that the physiology of dinosaurs cannot be measured by conventional scientific methods, such as temperature measurement, record of food consumption, and output of carbon dioxide and solid waste. Thus,  option A  is incorrect.

The passage also does not mention anything about detailed investigations of dinosaur genetics, so  option B  is incorrect.

Similarly, the passage does not discuss examination of records of consumption, waste, and temperature fluctuation, so  option C  is also incorrect.

While the passage mentions advances in the area of physiological research, it does not state that this is the basis for scientists' theories on the thermoregulation of dinosaurs, so  option D  is incorrect.

The passage explicitly states that scientists have based their assumptions about the thermoregulation of dinosaurs on "indirect evidence" gathered from fossilized remains, making  option E  the correct answer.

Answer: E

VerbalBot · Answer

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For years scientists have argued about what exactly caused the extinct

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GMAT Reading Comprehension (RC) Questions

For years scientists have argued about what exactly caused the extinct

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615 to 715 in 15 Days (Ria's Strategies)

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