Biologists have advanced two theories to explain why schooling of fish

Question

Biologists have advanced two theories to explain why schooling of fish occurs in so many fish species. Because schooling is particularly widespread among species of small fish, both theories assume that schooling offers the advantage of some protection from predators.

Proponents of theory A dispute the assumption that a school of thousands of fish is highly visible. Experiments have shown that any fish can be seen, even in very clear water, only within a sphere of 200 meters in diameter. When fish are in a compact group, the spheres of visibility overlap. Thus the chance of a predator finding the school is only slightly greater than the chance of the predator finding a single fish swimming alone. Schooling is advantageous to the individual fish because a predator's chance of finding any particular fish swimming in the school is much smaller than its chance of finding at least one of the same group of fish if the fish were dispersed throughout an area.

However, critics of theory A point out that some fish form schools even in areas where predators are abundant and thus little possibility of escaping detection exists. They argue that the school continues to be of value to its members even after detection.

They advocate theory B, the "confusion effect," which can be explained in two different ways. Sometimes, proponents argue, predators simply cannot decide which fish to attack. This indecision supposedly results from a predator's preference for striking prey that is distinct from the rest of the school in appearance. In many schools the fish are almost identical in appearance, making it difficult for a predator to select one. The second explanation for the "confusion effect" has to do with the sensory confusion caused by a large number of prey moving around the predator. Even if the predator makes the decision to attack a particular fish, the movement of other prey in the school can be distracting. The predator's difficulty can be compared to that of a tennis player trying to hit a tennis ball when two are approaching
simultaneously.   1 
 1. According to the passage, theory B states that which of the following is a factor that enables a schooling fish to escape predators?

(A) The tendency of fish to form compact groups
(B) The movement of other fish within the school
(C) The inability of predators to detect schools
(D) The ability of fish to hide behind one another in a school
(E) The great speed with which a school can disperse

2 
 2. According to the passage, both theory A and theory B have been developed to explain how

(A) fish hide from predators by forming schools
(B) forming schools functions to protect fish from predators ·
(C) schooling among fish differs from other protective behaviors
(D) small fish are able to make rapid decisions
(E) small fish are able to survive in an environment densely populated by large predators

3 
 3. According to one explanation of the "confusion effect," a fish that swims in a school will have greater advantages for survival if it

(A) tends to be visible for no more than 200 meters
(B) stays near either the front or the rear of a school
(C) is part of a small school rather than a large school
(D) is very similar in appearance to the other fish in the school
(E) is medium-sized

4 
 4. The author is primarily concerned with

(A) discussing different theories
(B) analyzing different techniques
(C) defending two hypotheses
(D) refuting established beliefs
(E) revealing new evidence

elizaanne · Accepted Answer

First of all, how I would map this out and take notes while reading would be something like this:

2 theories why schooling occurs--both assume protection from predators
Theory A--predator's chance of finding a fish in school<finding one if dispersed
Theory B--"Confusion effect"- 2 explanations
---1) pred cannot decide
---2) sensory confusion

Notes like these will help you keep track of where everything is and help you find specific information when you need it to answer a question.

Question 1 asks about theory B, so we know its in paragraph 3. 
A) is incorrect, because theory B says their are values beyond the group
B) seems promising, as sensory confusion from the movement is an explanation for the confusion effect
C) it incorrect, nowhere does it say that predators cannot detect entire schools
D) There is also nothing about hiding in theory B
E) also out of scope, because the passage says nothing about the groups dispersing
Thus, B is the answer

Question 2 asks about both theory A and B, so it it likely more dispersed throughout the passage or in paragraph one, which discusses both. This question also asks for something that is true for BOTH theories, so if it is not true for one, we can eliminate the whole answer
A) is wrong, because they are not hiding from predators, especially not in theory B.
B) this is promising, both theories do explain how forming schools protects from predators
C) there is no mention of other protective behaviors, so eliminate
D) nothing about small fish specifically, so eliminate
E) again, there is nothing about small and large, so eliminate
Thus, B is our answer

Question 3 asks about the confusion effect, so we know to look in paragraph 3
A) out of scope there is no mention of a specific number of meters
B) although this might be a logical leap in the real world, there is no mention of the fish's position in the school, so eliminate it
C)there is no mention of the size of the school, so eliminate
D) The fourth and fifth sentence in the 3rd paragraph explain why this is true 
E) no mention of size, so eliminate
D is our answer

Question 4 is a general question, so there is no specific part to go back to 
A) seems to be right, the author does discuss different theories
B) they are not techniques 
C) defending is too strong a word
D) he does not refute anything
E) no new evidence is revealed
Thus, the answer is A

aragonn · Answer

Main idea:

Author is trying to provide two theories why schooling occurs among fishes. author gave two theories, which are about protection from predetors.

Tone: author is not biased and just gave two theories.

A)Theory B stats that how movement of different fish can save them.
B)This can be answered from main idea 
C)Predators only go after distinct prey. fish take advantage of this revolve around to confuse them.
D)Go with the tone of the passage.

sobby · Answer

4. The author is primarily concerned with

(A) discussing different theories--yes theory A and B
(B) analyzing different techniques--only one technique is mentioned that is "schooling"
(C) defending two hypotheses--author is not defending anything
(D) refuting established beliefs--he is not refuting any belief
(E) revealing new evidence---no new evidence is outlined rather exisiting theory is discussed..

Hope it helped....

100mitra · Answer

RC#7 Long Passage {8 mins 4/4 correct}

Pharaphasing  
  Para 1:   Advanced two theories to explain schooling of fish.
  Para 2:   Theory A
- Formation of  compact group 
- The chance of a predator  finding the school is only slightly greater  unless fish were dispersed throughout an area
  Para 3:   Critics of theory A
- School continues to be of value to its members even after detection.
  Para 4:   The "confusion effect" two different way
- Predators  cannot decide  which fish to attack first
-  Sensory confusion  caused by a large number of preys moving around the predator
- the movement of other prey in the school can be distracting

1. According to the passage, 
theory B states that which of the following is a factor that enables a schooling fish to escape predators?  
(A) The tendency of fish to form compact groups
  Wrong:   as mentioned in passage in para 2 “Experiments have shown that any fish can be seen, even in very clear water, only within a sphere of 200 meters in diameter. When fish are in a compact group” refers to theory-A

(B) The movement of other fish within the school
  Correct: as mentioned in Passage Para 4 about “sensory confusion” – “Even if the predator makes the decision to attack a particular fish, the movement of other prey in the school can be distracting”

(C) The inability of predators to detect schools
  Wrong:   as mentioned in passage 2 “a predator's chance of finding any particular fish swimming in the school is much smaller than its chance of finding at least one of the same group of fish” refer to theory A

(D) The ability of fish to hide behind one another in a school
  Wrong:   Not mentioned in both the theory

(E) The great speed with which a school can disperse
  Wrong:   Not mentioned in both the theory

2. According to the passage, both theory A and theory B have been developed to explain how  
(A) fish hide from predators by forming schools
  Wrong:   its not about hiding from predators, its is about protection from predators by confusing, illusion of making appear big than predators

(B) forming schools’ functions to protect fish from predators 
  Correct: as mentioned in passage para 1 last line “both theories assume that schooling offers the advantage of some protection from predators“

(C) schooling among fish differs from other protective behaviors
  Wrong:   differ from other protective behaviors not mentioned, only one is mentioned to protect from predator

(D) small fish are able to make rapid decisions
  Wrong:   Easy elimination, this is not mentioned in passage

(E) small fish are able to survive in an environment densely populated by large predators
  Wrong:   No, the passage refer only discussion about the protection from predators, large and small variations not mentioned in the passage.

3. According to one explanation of the "confusion effect," a fish that swims in a school will have greater advantages for survival if it
  
(A) tends to be visible for no more than 200 meters
  Wrong:   this is in refers of theory A

(B) stays near either the front or the rear of a school
  Wrong:   it has to a part of school, either the front or the rear, makes no importance.

(C) is part of a small school rather than a large school
  Wrong:   Small school and large school advantages & disadvantages not mentioned in the passage

(D) is very similar in appearance to the other fish in the school
  Correct: as mentioned in the passage in para 4 “In many schools the fish are almost identical in appearance, making it difficult for a predator to select one.”

(E) is medium-sized
  Wrong:   Easy elimination, Not mentioned in the passage.

4. The author is primarily concerned with  
(A) discussing different theories
  Correct: passage mentioned theory A and theory B, and there some views from Proponents and critics  
 
(B) analysing different techniques
  Wrong:   there is no detailed examination of the techniques or structure of something

(C) defending two hypotheses
  Wrong:   No defending of any supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation

(D) refuting established beliefs
  Wrong:   There is no negative or counter argument mentioned in the passage to be disprove

(E) revealing new evidence
  Wrong:   Passage brief only about two theory, no new evidence mentioned in the passage

Sajjad1994 · Answer

Official Explanation

1. According to the passage, theory B states that which of the following is a factor that enables a schooling fish to escape predators?

Difficulty Level:   Easy

Explanation

Supporting idea 
This question depends on understanding what the passage states about theory B, the “confusion effect.”
One element of theory B is that predators may experience sensory confusion created by large numbers of moving fish in a school.

A.  The compactness of groups of schooling fish is an element of theory A, not theory B.

B.  Correct.   It is the movement of schooling fish around a predator that creates sensory confusion in the predator; this movement may distract the predator and help protect individual fish in the school.

C.  According to the passage’s description of theory A, predators are actually slightly more likely to detect schools than they are to detect individual fish.

D.  Theory B does not involve fish hiding behind one another but rather moving around the predator.

E.  The passage does not discuss the speed of dispersal of schools of fish.

Answer: B

Sajjad1994 · Answer

Official Explanation

2. According to the passage, both theory A and theory B have been developed to explain how

Difficulty Level:   Easy

Explanation

Supporting idea

The passage states in its first paragraph that two theories were developed to explain why schooling occurs in so many fish species and that they both assume that schooling helps protect fish from predators.

A.  While theory A involves an explanation of how schooling makes an individual fish less likely to be found by predators, theory B explains how schooling protects fish even when they are detected by predators.

B.  Correct.   Both theory A and theory B begin with the assumption that schooling provides protection
from predators, and each theory offers a different explanation for how that protection occurs.

C.  The passage does not discuss protective behaviors other than schooling.

D.  The decision-making ability of predators, not schooling fish, is discussed in the passage; schooling is presented as an instinctive behavior.

E.  The passage suggests that only theory B helps explain schooling behavior in environments where many predators, large or otherwise, are found, and that theory A explains schooling in areas where predators are not as abundant.

Answer: B

Sajjad1994 · Answer

Official Explanation

3. According to one explanation of the "confusion effect," a fish that swims in a school will have greater advantages for survival if it

Difficulty Level:   Easy

Explanation

Inference

The  “confusion effect”  is discussed in the third and fourth paragraphs. The first explanation of the  “confusion effect”  proposes that because predators prefer to select distinctive prey, they find it difficult to select one fish from among many that look the same.

A.  The 200-meter visibility of fish is part of the explanation for theory A, not theory B (the “confusion effect”).

B.  The location of an individual fish within a school is not discussed in the passage as being important to the “confusion effect.”

C.  The size of a school of fish is not discussed as an element of the  “confusion effect.”

D.  Correct.   Because predators, according to the “confusion effect,” prefer to select prey that is distinct from the rest of the school, a fish that is similar in appearance to the other fish in its school would most likely enjoy a survival advantage.

E.  The size of a fish relative to the other fish in its school would most likely contribute to its ability to survive: that is, if it resembled other fish in size, it would be safer, based on what the passage says about the  “confusion effect.”  Furthermore, the passage gives no reason to think that merely being medium-sized would confer any advantage (unless the other fish were medium-sized as well).

Answer: D

Sajjad1994 · Answer

Official Explanation

4. The author is primarily concerned with

Difficulty Level:   Easy

Explanation

Main idea

Determining the author’s primary concern depends on understanding the focus of the passage as a whole. The author presents two theories that purport to account for why fish, particularly small fish, tend to school and explains the arguments of proponents of each theory.

A.  Correct.   The author discusses two theories—identified as theory A and theory B—that account for the tendency of fish to school.

B.  The author is not concerned with different techniques in the passage.

C.  The two theories of why the fish school could be referred to as hypotheses, but the author is not primarily concerned with defending them; rather, the passage explains how each attempts to account for the phenomenon in question.

D.  The author presents, rather than refutes, beliefs about why fish tend to school.

E.  The author reveals no evidence, new or otherwise, in the passage. The passage is a general discussion of scientific opinions based on existing evidence.

Answer: B

VerbalBot · Answer

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Biologists have advanced two theories to explain why schooling of fish

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Biologists have advanced two theories to explain why schooling of fish

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