A mysterious phenomenon is the ability of over-water migrants to trave

Question

A mysterious phenomenon is the ability of over-water migrants to travel on course. Birds, bees, and other species can keep track of time without any sensory cues from the outside world, and such "biological clocks" clearly con-tribute to their "compass sense." For example, they can use the position of the Sun or stars, along with the time of day, to find north. But compass sense alone cannot explain how birds navigate the ocean: after a flock travelling east is blown far south by a storm, it will assume the proper north-easterly course to compensate. Perhaps, some scientists thought, migrants determine their geographic position on Earth by celestial navigation, almost as human navigators use stars and planets, but this would demand of the animals  a fantastic map sense . Researchers now know that some species have a magnetic sense, which might allow migrants to determine their geographic location by detecting variations in the strength of the Earth's magnetic field.    1 
 B 
 Q1. The main idea of the passage is that

(A) migration over land requires a simpler explanation than migration over water does
(B) the means by which animals migrate over water are complex and only partly understood
(C) the ability of migrant animals to keep track of time is related to their magnetic sense
(D) knowledge of geographic location is essential to migrants with little or no compass sense
(E) explanations of how animals migrate tend -to replace, rather than build on, one another

2 
 A 
 Q2. It can be inferred from the passage that if the flock of birds described were navigating by compass sense alone, they would, after the storm, fly

(A) east 
(B) north 
(C) northwest 
(D) south 
(E) southeast

3 
 B 
 Q3. In maintaining that migrating animals would need  "a fantastic map sense"  to determine their geographic position by celestial navigation, the author intends to express

(A) admiration for the ability of the migrants
(B) scepticism about celestial navigation as an explanation
(C) certainty that the phenomenon of migration will remain mysterious
(D) interest in a new method of accounting for over-water migration
(E) surprise that animals apparently navigate in much the same way that human beings do

4 
 A 
 Q4. Of the following descriptions of migrating animals, which most strongly suggests that the animals are depending on magnetic cues to orient themselves?

(A) Pigeons can properly readjust their course even when flying long distances through, exceedingly dense fogs.
(B) Bison are able to reach their destination by passing through a landscape that has been partially altered by a recent fire.
(C) Elephants are able to find grounds that some members of the herd have never seen before.
(D) Swallows are able to return to a given spot at the same time every year.
(E) Monarch butterflies coming from different parts of North America are able to arrive at the same location each winter.

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Passage # 96 Date: 09-Mar-2021
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LipiSinha · Accepted Answer

Q1. 
A. is Out of scope. The author nowhere in the passage compares migration on land to migration on water.

B. is correct. The author in the beginning of passage refers to the ability of over water migrants to travel on course as a "mysterious phenomenon". He goes on to talk about the inbuilt biological clocks in the flying species, but in the very next line argues that this alone does not explain how the birds navigate the ocean. Celestial navigation in birds also seems like a far-fetched idea to the author. He concludes by saying that Some species have a magnetic sense.
 
C. Magnetic sense does not allow migrant animals to keep track of time. It allows them to determine their geographic location.

D. is out of scope. The passage is talking about how migrant animals stick to their course over water.

E. is irrelevant. The passage nowhere suggests that explanations of how animals migrate tend -to replace.

Q2.
 A. is the correct answer. If the birds are traveling East (going right from North) and they are blown far South by the storm, and they are traveling on compass sense alone then they would keep going in the same direction i.e., East.

Q3.
A. The author does not express admiration. He refutes the idea that the migrant animals use celestial navigation as a way to migrate.

B. is the correct answer. The author says that some scientists thought that migrant animals use celestial navigation to navigate over oceans. However, he thinks this to be a flawed explanation as this would require the animals to have a "fantastic map sense".

C. In this line, the author doesn't show certainty of any sort. He is simply saying that the idea of migrant animals using celestial navigation to stay on course is not logically justified.

D. The author does not use this phrase to show any interest in a new method.

E. The author is not showing surprise. He is expressing his doubt.

Q4.
 A. is correct. In exceedingly dense fogs when very little or almost nothing can be seen, only magnetic sense can justify how the pigeons readjust their course properly.
 
B. is out of scope. This has absolutely no relation to the magnetic sense of animals.

C. is out of scope. It merely refers to wandering capabilities/skills of elephants.

D. This does not showcase the magnetic sense of swallows. Maybe the weather was clear, and they did not have to readjust their course at all.

E. Same as D.

Anshuman0902 · Answer

explain q no 2 please 
thanx

Sajjad1994 · Answer

Read the lines in the passage:

"after a flock travelling   east   is blown far south by a storm, it will  assume the proper  north-easterly  course to compensate. "

It says that the birds will keep their direction hence  A.

Thank you

bidskamikaze · Answer

Primary Purpose of the passage: To speculate on the mystery of navigational method by which some living beings navigate.

Q1. The main idea of the passage is that

(A) migration over land requires a simpler explanation than migration over water does -  Incorrect. over land vs over water is not the concern 
(B) the means by which animals migrate over water are complex and only partly understood -  Correct. 
(C) the ability of migrant animals to keep track of time is related to their magnetic sense -  Incorrect. "Magnetic sense" is one of the possible theories; "IS": too strong. 
(D) knowledge of geographic location is essential to migrants with little or no compass sense-  Incorrect. Debatable theory. 
(E) explanations of how animals migrate tend -to replace, rather than build on, one another -  Incorrect. Can't be inferred. 
Answer B.

Q2. It can be inferred from the passage that if the flock of birds described were navigating by compass sense alone, they would, after the storm, fly
 (A) east 
(B) north
(C) northwest
(D) south
(E) southeast

Answer is A.   "But compass sense alone cannot explain how birds navigate the ocean: after a flock travelling east is blown far south by a storm, it will assume the proper north-easterly course to compensate."  
This statement shows that if the birds navigated by using an internal compass alone, then they would have continued to move eastward.

Q3. In maintaining that migrating animals would need  "a fantastic map sense"  to determine their geographic position by celestial navigation, the author intends to express

(A) admiration for the ability of the migrants
 (B) scepticism about celestial navigation as an explanation 
(C) certainty that the phenomenon of migration will remain mysterious
(D) interest in a new method of accounting for over-water migration
(E) surprise that animals apparently navigate in much the same way that human beings do

Answer B. The intent of using the phrase  "a fantastic map sense"  is to imply that celestial navigation as an explanation is highly improbable.

Q4. Of the following descriptions of migrating animals, which most strongly suggests that the animals are depending on magnetic cues to orient themselves?

(A) Pigeons can properly readjust their course even when flying long distances through, exceedingly dense fogs. -  Correct. If dense fog is prevalent, then the pigeons will not be able to take celestial cues and geographical cues. Then, the only possible explanation would be magnetic cues. 
(B) Bison are able to reach their destination by passing through a landscape that has been partially altered by a recent fire. -  Incorrect. Celestial cues will also be possible. 
(C) Elephants are able to find grounds that some members of the herd have never seen before. -  Incorrect. All type of cues are possible. 
(D) Swallows are able to return to a given spot at the same time every year. -  Incorrect. All type of cues are possible. 
(E) Monarch butterflies coming from different parts of North America are able to arrive at the same location each winter.

Answer A.

VerbalBot · Answer

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A mysterious phenomenon is the ability of over-water migrants to trave

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