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Difficulty:
65%
(hard)
Question Stats:
66% (02:10) correct
34%
(02:25)
wrong
based on 1392
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Paleontologist: Sifrhippus, a miniature horselike animal, lived about 56 million years ago. The average weight of Sifrhippus adults declined from 5.4 to 3.9 kilograms during a period of climatic warming that lasted about 175,000 years, then rose as the climate cooled again. The most likely explanation is that smaller mammals can shed heat more easily than larger ones—Sifrhippus must have adapted to the hot climate by shrinking because larger individuals would more often have died from overheating.
Which of the following would, if true, most strongly support the paleontologist's hypothesis?
A. The climatic warming shrank Sifrhippus habitats, and larger habitats can generally support larger animals.
B. Before the climate warming period, Sifrhippus went through several changes in average body size and weight that did not coincide with changes in climate.
C. Several species of small mammals went extinct during the period of climatic warming, while many larger species thrived.
D. Sifrhippus populations increased in numbers during the period of climatic warming, then decreased again as the climate cooled.
E. During the climatic warming period, Sifrhippus adults weighed more, on average, in populations in cooler habitats.
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Which of the following would, if true, most strongly support the paleontologist's hypothesis?
A. The climatic warming shrank Sifrhippus habitats, and larger habitats can generally support larger animals.
B. Before the climate warming period, Sifrhippus went through several changes in average body size and weight that did not coincide with changes in climate.
C. Several species of small mammals went extinct during the period of climatic warming, while many larger species thrived.
D. Sifrhippus populations increased in numbers during the period of climatic warming, then decreased again as the climate cooled.
E. During the climatic warming period, Sifrhippus adults weighed more, on average, in populations in cooler habitats.
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Paleontologist: Sifrhippus, a miniature horselike animal, lived about 56 million years ago. The average weight of Sifrhippus adults declined from 5.4 to 3.9 kilograms during a period of climatic warming that lasted about 175,000 years, then rose as the climate cooled again. The most likely explanation is that smaller mammals can shed heat more easily than larger ones—Sifrhippus must have adapted to the hot climate by shrinking because larger individuals would more often have died from overheating.
The paleontologist's hypothesis is the following:
The most likely explanation is that smaller mammals can shed heat more easily than larger ones—Sifrhippus must have adapted to the hot climate by shrinking
The support for the hypothesis is the following:
The average weight of Sifrhippus adults declined from 5.4 to 3.9 kilograms during a period of climatic warming that lasted about 175,000 years, then rose as the climate cooled again.
larger individuals would more often have died from overheating
So, the paleontologist reasons that, since Sifrhippus's size decreased when the climate warmed and increased when it cooled and since larger individuals would more often have died in hot conditions, the reason why Sifrhippus's size decreased is that "Sifrhippus ... adapted to the hot climate by shrinking."
Which of the following would, if true, most strongly support the paleontologist's hypothesis?
This question is a Strengthen question, and the correct answer will strengthen the support already provided or provide additional new support for the conclusion.
A. The climatic warming shrank Sifrhippus habitats, and larger habitats can generally support larger animals.
This choice weakens rather than strengthens the argument.
After all, if this choice is true, then it could be the case that, rather than to shed heat, Sifrhippus shrank because Sifrhippus habitats shank.
In other words, this choice indicates that there is a reasonable alternative explanation for Sifrhippus's shrinking and thus makes it less likely that the paleontologist's hypothesis is correct.
Eliminate.
B. Before the climate warming period, Sifrhippus went through several changes in average body size and weight that did not coincide with changes in climate.
This choice weakens rather than strengthens the argument.
After all, if Sifrhippus went through several changes in average body size and weight that did not coincide with changes in climate, then the types of changes in Sifrhippus's size that occurred when the climate did change were also going on when the climate didn't change. In other words, the effects occurred without the supposed cause.
The fact that the effects occurred without climate changes indicates that climate changes may not have been the cause even when climate changes did occur.
Eliminate.
C. Several species of small mammals went extinct during the period of climatic warming, while many larger species thrived.
This choice may seem to affect the strength of argument, but actually, it has no effect.
The passage states as fact that smaller animals can shed heat more easily and that larger animals would more often have died in hot conditions. So, even if this choice is true, and some particular species of small animals went extinct and some particular larger species thrived during periods of warming, it remains the case that shrinking could have helped Sifrhippus survive when it was hot.
Eliminate.
D. Sifrhippus populations increased in numbers during the period of climatic warming, then decreased again as the climate cooled.
This choice has no clear effect on the strength of the argument.
After all, there's no clear relationship between the populations increasing and decreasing and Sifrhippus's size decreasing and then increasing.
Eliminate.
E. During the climatic warming period, Sifrhippus adults weighed more, on average, in populations in cooler habitats.
This choice is interesting.
After all, it confirms the relationship between Sifrhippus's size and the climate by showing that, even within one time period, Sifrhippus adults were smaller where it was warm and larger where it was cooler.
By showing that the relationship between size and climate held even within one time period, this choice helps to eliminate other variables that could have changed over time and thus confirm that the key factor causing Sifrhippus to be smaller or larger was Sifrhippus's adaptation to different temperatures.
Thus, this choice strengthens the case for the hypothesis.
Keep.
Correct answer: E
_________________
The paleontologist's hypothesis is the following:
The most likely explanation is that smaller mammals can shed heat more easily than larger ones—Sifrhippus must have adapted to the hot climate by shrinking
The support for the hypothesis is the following:
The average weight of Sifrhippus adults declined from 5.4 to 3.9 kilograms during a period of climatic warming that lasted about 175,000 years, then rose as the climate cooled again.
larger individuals would more often have died from overheating
So, the paleontologist reasons that, since Sifrhippus's size decreased when the climate warmed and increased when it cooled and since larger individuals would more often have died in hot conditions, the reason why Sifrhippus's size decreased is that "Sifrhippus ... adapted to the hot climate by shrinking."
Which of the following would, if true, most strongly support the paleontologist's hypothesis?
This question is a Strengthen question, and the correct answer will strengthen the support already provided or provide additional new support for the conclusion.
A. The climatic warming shrank Sifrhippus habitats, and larger habitats can generally support larger animals.
This choice weakens rather than strengthens the argument.
After all, if this choice is true, then it could be the case that, rather than to shed heat, Sifrhippus shrank because Sifrhippus habitats shank.
In other words, this choice indicates that there is a reasonable alternative explanation for Sifrhippus's shrinking and thus makes it less likely that the paleontologist's hypothesis is correct.
Eliminate.
B. Before the climate warming period, Sifrhippus went through several changes in average body size and weight that did not coincide with changes in climate.
This choice weakens rather than strengthens the argument.
After all, if Sifrhippus went through several changes in average body size and weight that did not coincide with changes in climate, then the types of changes in Sifrhippus's size that occurred when the climate did change were also going on when the climate didn't change. In other words, the effects occurred without the supposed cause.
The fact that the effects occurred without climate changes indicates that climate changes may not have been the cause even when climate changes did occur.
Eliminate.
C. Several species of small mammals went extinct during the period of climatic warming, while many larger species thrived.
This choice may seem to affect the strength of argument, but actually, it has no effect.
The passage states as fact that smaller animals can shed heat more easily and that larger animals would more often have died in hot conditions. So, even if this choice is true, and some particular species of small animals went extinct and some particular larger species thrived during periods of warming, it remains the case that shrinking could have helped Sifrhippus survive when it was hot.
Eliminate.
D. Sifrhippus populations increased in numbers during the period of climatic warming, then decreased again as the climate cooled.
This choice has no clear effect on the strength of the argument.
After all, there's no clear relationship between the populations increasing and decreasing and Sifrhippus's size decreasing and then increasing.
Eliminate.
E. During the climatic warming period, Sifrhippus adults weighed more, on average, in populations in cooler habitats.
This choice is interesting.
After all, it confirms the relationship between Sifrhippus's size and the climate by showing that, even within one time period, Sifrhippus adults were smaller where it was warm and larger where it was cooler.
By showing that the relationship between size and climate held even within one time period, this choice helps to eliminate other variables that could have changed over time and thus confirm that the key factor causing Sifrhippus to be smaller or larger was Sifrhippus's adaptation to different temperatures.
Thus, this choice strengthens the case for the hypothesis.
Keep.
Correct answer: E
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General Discussion
MartyMurray: In strengthening questions, I was taught that there is always an underlying assumption. This is the reason that I often fail with strengthening questions as I fail to find the underlying assumptions. However, at times in official questions I feel that all dots are connected and there is no possibility to place an assumption between premise and conclusion. Is my observation correct? And if yes, should I adopt my evaluation process with such questions?
Posts: 24
SergejK
SergejK
Understanding how to strengthen or weaken an argument was a challenge for me, as I once believed that simply validating the underlying assumption was enough to judge an option's validity. However, these question types are more complex.
To strengthen an argument, option can:
- Introduce logical information or new facts that support the argument and affirm the conclusion,
- Reformulate the conclusion to make it more robust, or
- Confirm the validity of an assumption.
Conversely, to weaken an argument, option might:
- Present logical information or new facts that refute the argument and negate the conclusion,
- Challenge an underlying assumption, or
- Reverse the cause-and-effect relationship.
I hope this clarification is beneficial.
MartyMurray
Hi MartyMurray,
I actually marked D for this. My reasoning was since it is mentioned in the passage that 'larger individuals would more often have died from overheating' and Option D tells that 'Sifrhippus populations increased in numbers during the period of climatic warming' therefore this supports that Sifrhippus must have adapted to hot climate by shrinking.
Can you please help me with this logic?
GMAT Focus 1: 645 Q86 V81 DI78
Posts: 8
Conclusion:
Smaller mammals can shed heat more easily than larger ones.
Premises:
1)A horse mini animal loses weight during climatic warming which lasted about 175k years.
2)It gained weight after the climate cooled again,
3)The animal adopted to the hot climate by shrinking;
4)Larger animals would more often have died from overheating.
A.)Habits could be shrank as a result of climatic warming. Irrelevant.
B)The animal’s weight has been changed not coinciding with climate changes. Weaken premises 1)&2).
C)Larger species survived more than small mammals during climatic warming. Weaken premise 4).
D)Populating number is positive related with climatic warming. Irrelevant.
E)The animal weighted more in cooling habitat during the climatic warming period. Strengthen the premise 2).
Smaller mammals can shed heat more easily than larger ones.
Premises:
1)A horse mini animal loses weight during climatic warming which lasted about 175k years.
2)It gained weight after the climate cooled again,
3)The animal adopted to the hot climate by shrinking;
4)Larger animals would more often have died from overheating.
A.)Habits could be shrank as a result of climatic warming. Irrelevant.
B)The animal’s weight has been changed not coinciding with climate changes. Weaken premises 1)&2).
C)Larger species survived more than small mammals during climatic warming. Weaken premise 4).
D)Populating number is positive related with climatic warming. Irrelevant.
E)The animal weighted more in cooling habitat during the climatic warming period. Strengthen the premise 2).
Why cant it be D as it indicates that smaller animals survived ?
Prak0709
The hypothesis is specifically that smaller body size evolved to shed heat better. Option D only states the population increased during warming. A population increase could happen for many reasons (more food, fewer predators) and does not directly support the claim that smaller individual body size was the adaptive advantage. It's consistent with the idea but doesn't strengthen the causal link between heat and smaller anatomy. Option E directly supports that link by showing size varied with local temperature.
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