Naturalists have long studied the ability of North American forest bir

Question

Naturalists have long studied the ability of North American forest birds to survive extremely cold overnight temperatures in winter. For example, nuthatches sleep in cavities such as tree hollows or holes dug into snowdrifts, retaining heat closer to the body and thus saving energy by reducing the need for shivering. Chickadees induce torpor, saving energy by allowing their body temperatures to decline drastically. Grosbeaks stay close to trees whose seeds contain sufficient fat to fuel shivering. But the survival of one species, the kinglet, remains something of a mystery.

There are two reasons for this. First, although kinglets are tiny—about 9 cm long including the tail—they maintain extremely high body temperatures at conditions well below freezing. According to the physical laws of heating and cooling, kinglets would lose heat at a rate about 75 percent faster than birds twice their mass—chickadees, for example—and so would have to consume and burn 75 percent more food per unit of body mass than the larger birds to maintain the same body temperature. The insulation provided by feathers, which, similarly to other northern birds, make up about 25 percent of the kinglet's mass, accounts for some of its heat-retaining capability but does not explain how kinglets manage to survive as well in cold climates as do the larger birds. Because smaller birds have a lesser absolute amount of insulation than larger birds, they would cool even faster than predicted by body mass alone.

The second reason kinglet survival is so remarkable is that, unlike most bird species that remain in cold climates during winter, their diet consists exclusively of insects. Researchers wonder how it is possible for kinglets, birds that do not cache food and are known not to forage at night, to gather and consume the necessary amount of insects each short winter day. The question is more vexing considering that a kinglet's stomach when filled to capacity contains only enough food to keep it warm for one hour.

A partial explanation is that kinglets store fat; kinglet body fat can triple in the course of a day. Nevertheless, this increase accounts for only about half the energy needed to maintain the kinglet's body temperature overnight. Researchers once theorized that torpor might make up the difference, but found no evidence of torpor in kinglets. Another theory, which is still untested but which may be borne out by a recent study of goldcrests, a related species, is that kinglets cluster together at night. Kinglets flock in groups of twos and threes during the day; while such small groups alone could not maintain such high body temperatures, it is hypothesized that after nightfall several groups in a region may find each other by means of calling and consolidate in a central location.    1 
 1. Which one of the following most accurately states the central idea of the passage?

(A) Kinglets are able to survive the coldest winter nights despite a size, physiology, and behavior that should make them vulnerable to low temperatures.
(B) Researchers have tested several theories in their attempts to answer the question of how kinglets survive very low temperatures.
(C) Kinglets are unique among small birds due to a survival rate in extremely low temperatures that is twice that of larger birds.
(D) The kinglet's tiny size complicates the attempts by researchers to observe how it survives the extremely low temperatures of winter nights.
(E) Researchers do not yet fully understand the behavioral and physiological factors that allow kinglets to survive the coldest winter nights.

2 
 2. Which one of the following generalizations best captures the reasoning behind the rejection of the theory that torpor explains the kinglet's ability to survive extremely cold overnight temperatures?

(A) Absence of evidence for a behavior can be taken as evidence for absence of the behavior.
(B) Dissimilar species tend to exhibit dissimilar behaviors.
(C) The existence of evidence for a theory is not enough to establish the theory as true.
(D) A theory can be taken as false if several initial tests fail to produce conclusive results.
(E) Acceptance of a theory requires a consensus in the scientific community.

3 
 3. According to the passage, the physical laws of heating and cooling suggest that in order to maintain body temperature in winter, kinglets must

(A) consume more food per unit of body mass than any other bird of equivalent mass does
(B) consume enough food to keep their stomachs continuously filled to capacity
(C) consume more food than larger birds do
(D) consume more food per unit of body mass than birds twice their mass do
(E) consume less food per unit of body mass than larger birds with less insulation do

4 
 4. The passage suggests that the author most likely regards the hypothesis that groups of kinglets cluster together on cold winter nights as

(A) almost certainly true since all other explanations have been eliminated
(B) feasible given that kinglets flock in groups during the day
(C) a possibility that, though unlikely, is the only option left to explore
(D) well established by a recent study of goldcrests
(E) the hypothesis most widely discussed in the scientific community

5 
 5. The author cites all of the following as contributing to the mystery of kinglet survival in extremely cold overnight winter temperatures EXCEPT:

(A) the kinglet's stomach capacity
(B) the kinglet's relation to goldcrests
(C) the kinglet's limited diet
(D) the kinglet's small body mass
(E) the kinglet's lack of night foraging

6 
 6. The author mentions nuthatches, chickadees, and grosbeaks primarily to

(A) introduce various methods of surviving extremely cold overnight temperatures employed by North American forest birds
(B) identify which North American forest birds successfully cope with extremely low overnight temperatures
(C) show that adaptation to extremely cold overnight temperatures is found only among North American forest birds
(D) present strategies of surviving extremely cold overnight temperatures also employed by kinglets
(E) prove that each bird species employs a unique approach to surviving extremely cold overnight temperatures

7 
 7. The passage suggests that the author would most likely agree with which one of the following?

A. Naturalists have yet to achieve much understanding of the ability of small birds to survive extremely cold temperatures overnight.
B. The kinglet's diet may be found to be high enough in fat to provide sufficient energy to account for its survival.
C. The behavior of kinglets includes calls that trigger the impulse to flock with other members of its species.
D. Nocturnal behavior observed in species related to kinglets might reasonably be presumed to occur also among kinglets.
E. The kinglet adapts to extremely low temperatures by drastically reducing its body temperature.

GREAccount · Answer

The passage suggests that the author would most likely agree with which one of the following?

A. Naturalists have yet to achieve much understanding of the ability of small birds to survive extremely cold temperatures overnight.
B. The kinglet's diet may be found to be high enough in fat to provide sufficient energy to account for its survival.
C. The behavior of kinglets includes calls that trigger the impulse to flock with other members of its species.
D. Nocturnal behavior observed in species related to kinglets might reasonably be presumed to occur also among kinglets.
E. The kinglet adapts to extremely low temperatures by drastically reducing its body temperature. please ans the question of April 3rd passage

Sajjad1994 · Answer

Explanation

7. The passage suggests that the author would most likely agree with which one of the following?

Difficulty Level:   700

Explanation

The correct answer is  D . Nocturnal behavior observed in species related to kinglets might reasonably be presumed to occur also among kinglets.

This can be inferred from the passage where it is mentioned that a recent study of goldcrests, a related species to kinglets, suggests that kinglets may also cluster together at night. The passage states, "Another theory, which is still untested but which may be borne out by a recent study of goldcrests, a related species, is that kinglets cluster together at night." This suggests that the behavior of clustering together at night, observed in goldcrests, may also be presumed to occur among kinglets as they are related species. Therefore,  option D  is the most likely statement that the author would agree with based on the information provided in the passage.

Answer: D

Sajjad1994 · Answer

Explanation

2. Which one of the following generalizations best captures the reasoning behind the rejection of the theory that torpor explains the kinglet's ability to survive extremely cold overnight temperatures?

Explanation

The passage discusses the mystery surrounding the kinglet's ability to survive in extremely cold temperatures and its unique characteristics compared to other bird species. One theory considered by researchers to explain this survival is the possibility of torpor, a state of decreased physiological activity, as seen in other birds like chickadees. However, the passage states that researchers found no evidence of torpor in kinglets, which means they did not observe any behavior suggesting torpor is employed by kinglets.

The generalization  "Absence of evidence for a behavior can be taken as evidence for absence of the behavior"  aligns with the rejection of the torpor theory. The researchers did not find any evidence of torpor in kinglets, which weakens the support for this explanation. Just because torpor is observed in other bird species like chickadees does not necessarily mean it applies to all birds, especially when specific evidence of torpor is lacking in kinglets.

Option (A)  captures this reasoning, as it highlights that when there is an absence of evidence supporting a particular behavior (torpor in this case), it can be seen as evidence suggesting that the behavior (torpor) may not be present in the kinglet.

Other options, such as  (B)  and  (D) , are not directly relevant to the specific scenario presented in the passage, and  (C)  and  (E)  do not specifically address the issue of evidence for the theory of torpor in kinglets. Therefore,  (A)  is the best choice that aligns with the reasoning in the passage.

Answer: A

Vaishali2004 · Answer

Can you please explain why Option C in 7th question is incorrect?

Sajjad1994 · Answer

C. "The behavior of kinglets includes calls that trigger the impulse to flock with other members of its species."

While the passage does mention the theory that kinglets might cluster together at night and suggests that they could find each other by means of calling and consolidate in a central location, it does not explicitly state that their behavior includes calls triggering the impulse to flock. The passage does discuss the possibility of calling as a means of communication and clustering, but it doesn't conclusively affirm that kinglets have specific calls that trigger the impulse to flock with other members of their species.

In contrast, option (D) is a more general and accurate interpretation of the passage:

D. "Nocturnal behavior observed in species related to kinglets might reasonably be presumed to occur also among kinglets."

The passage discusses how the behavior of other related species, such as goldcrests, might provide insights into the behavior of kinglets. It suggests that the clustering behavior observed in goldcrests at night could potentially be applicable to kinglets as well. This is a more valid and supported inference based on the information provided in the passage.

Answer: D

Naturalists have long studied the ability of North American forest bir

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Naturalists have long studied the ability of North American forest bir

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