The ‘trophic contamination hypothesis’ posits that shorebirds accumula

Question

New Project RC Butler 2019  -  Practice 2 RC Passages Everyday   
Passage # 42, Date : 21-FEB-2019
 This post is a part of New Project RC Butler 2019 .  Click here for Details

The ‘trophic contamination hypothesis’ posits that shorebirds accumulate industrial and urban pollution at stopover sites, toxins that are subsequently released in sudden high doses as fat is burned during migratory flights, disrupting the bird’s ability to make migratory decisions.
3. the author implies that foreign ecosystems have which potential effect on shorebirds?

A They can make a bird more vulnerable to predators.
B They can expose shorebirds to foreign toxins.
C They can diminish a bird’s ability to navigate.
D They can lead to a reduction in the bird’s weight.
E They can cause a bird to become separated from its flock.

I believe the answer to this question would be B as per the highlighted region.
Experts, please guide.
Thank you.

One promising line of research involves organochlorines, toxins deposited on mudflats in the 1970s and 1980s, now buried by sediments but finally close enough to the surface to be of issue to foraging shorebirds. Organochlorines should be more accessible to long-billed shorebirds that probe deeply for prey than to short-billed species that forage at or near the surface. We predict that an increased number of long-billed shorebirds will either be unable to migrate or will be found along an aberrant flight path   1 
 1. The most immediate effect on birds that have accumulated toxins in their fat deposits is

A a tendency to navigate along a divergent flight path
B an inability to realize when they have eaten a sufficient amount of food
C a diminished capacity to retrace their migratory route
D an increased likelihood to exhibit aggression towards other species
E an increased likelihood to exhibit aggression towards other species

2 
 2. According to the passage, the long-billed shorebird is expected to be more likely than the short-billed shorebird to have trouble migrating because

A it is more vulnerable to the effects of organochlorines
B it typically is unable to differentiate between a foreign ecosystem and a familiar one
C it stops feeding before it is fully satiated
D it grazes in parts of the mudflat in which the surface is known to have a higher concentration of organochlorines
E it digs deeper into the earth and is therefore more likely to encounter toxins

3 
 3. the author implies that foreign ecosystems have which potential effect on shorebirds?

A They can make a bird more vulnerable to predators.
B They can expose shorebirds to foreign toxins.
C They can diminish a bird’s ability to navigate.
D They can lead to a reduction in the bird’s weight.
E They can cause a bird to become separated from its flock.

Difficulty Level:   700

AdityaHongunti · Accepted Answer

apovit 
Firstly , there is nowhere in the passage which may suggest that " unable to migrate LEADS to reduction !! ...rather it is the opposite !!! reduction in weight that is less fat intake leads to unabl to migrate

towards he question :

I'll explain to you step by step !!!

First lets ubderstad first para :

understand: "TCH" states a hypothesis . It says that Accumulation of pollution in shorebids leads to intake of more toxins simultaneously with burning of fat.. It measn that when the bird is migrating obviously it needs energy to do so and hence it needs fat...but as it passes from the "stopover sites" it intakes toxins too ...now this consequently leads to bird's ABILITY to make mig decision !!

map : migration >> fat burning>> passing from pollution >> intake of toxins>> disruption in ability !!

Understand: Now the author puts forward an example of the hypothesis (to explain) . he says when the bird intakes LARGE DOSES of toxins the bird might feel that it is actually satiated ( feeling that i am full or satisfied :food wise) ..But due to this FALSE SATIATION the bird may not actually consume enough calories to make its migration !!

Understand : Author here presents the "findings" of a study: out of the shorebirds  that were unable t migrate  (please note this modifier) , some weighted as 20% less than the avg shorebird (general)

Understand : first of all always make note when there are pronouns (referances) : here "such findings" refers back to the findings the author present in earlier sentence (study FOUND that) ... so the author claims that the explanation behing "the findings : less weight" is due to Tropic contamination or by landing on foreign eco is not clear !!

Para summary : A hypothesus is presneted and explained with the hel nof an example. Finding of a study are presented. Claim is made abou the explanation about the findings of the study !!

3. the author implies that foreign ecosystems  have which potential effect  on shorebirds?

Note that the "Foreign econsystem" was stated as POSSIBLE explanatio to the finding of the study !!! so if this the explanation then in other words this is the cause.. and then what is the effect of this??? it is the reduced weight .. remember the question states "potential" effect... So we dont need conclusive answer !!

A They can make a bird  more vulnerable t o predators.
not mentioned

B They can expose shorebirds to foreign toxins.
- the foregin ecosystem is not linked to toxins ... ON THE CONTRARY it is alternative explnation to toxic contamination !!! if even forein lands had toxic things hy would author make it a distinct piunt???mBy giving an alternative to toxic pollution he wants to say that the "foreign ECOSYSTEM" which may imply the diet may change accoding to the availability of food on the foreign land !!!

C They can diminish a bird’s ability to navigate.
- NOT a direct link !!!

D They can lead to a reduction in the bird’s weight.
- This is the direct potentioal effect becasue author makes it ckear by trying to provide explanations for this finding !!
 
E They can cause a bird to become  separated from its flock. 
- useless

pk123 · Answer

1. The most immediate effect on birds that have accumulated toxins in their fat deposits is

A a tendency to navigate along a divergent flight path --  close answer 
B an inability to realize when they have eaten a sufficient amount of food--  close answer 
C a diminished capacity to retrace their migratory route--  close answer 
D an increased likelihood to exhibit aggression towards other species ---  not talked in the passage 
E an increased likelihood to exhibit aggression towards other species -- not talked in the passage

Now out of the top 3 close answers, think of effects of toxins on shorebirds as 3 step process 1) birds eat toxins that make them realise they have eaten sufficient "For example, large contaminant doses might hamper refueling by altering the satiation signal in shorebirds so that they do not accumulate sufficient fat for migration"
2) Now birds will take flight and hence they may taken divergent path or unable to retrace migratory route

Hence option B makes more sense as also supported by passage an logically out of the top 3 close answers, serial order of activities will happen in this particular order

Please hit kudos if you like the explanation

TaN1213 · Answer

The ‘trophic contamination hypothesis’ posits that  shorebirds accumulate industrial and urban pollution at stopover sites,  toxins that are subsequently released in sudden high doses as fat is burned during migratory flights, disrupting the bird’s ability to make migratory decisions. 
3. the author implies that foreign ecosystems have which potential effect on shorebirds?

A They can make a bird more vulnerable to predators.
B They can expose shorebirds to foreign toxins.
C They can diminish a bird’s ability to navigate.
D They can lead to a reduction in the bird’s weight.
E They can cause a bird to become separated from its flock.

I believe the answer to this question would be B as per the highlighted region.
Experts, please guide.
Thank you.

MYGMAT2019 · Answer

1. The most immediate effect on birds that have accumulated toxins in their fat deposits is

A a tendency to navigate along a divergent flight path
B an inability to realize when they have eaten a sufficient amount of food- CORRECT (For example, large contaminant doses might hamper  refueling by altering the satiation signal  in shorebirds so that they do not accumulate sufficient fat for migration)
C a diminished capacity to retrace their migratory route
D an increased likelihood to exhibit aggression towards other species
E an increased likelihood to exhibit aggression towards other species

2. According to the passage, the long-billed shorebird is expected to be more likely than the short-billed shorebird to have trouble migrating because

A it is more vulnerable to the effects of organochlorines
B it typically is unable to differentiate between a foreign ecosystem and a familiar one
C it stops feeding before it is fully satiated
D it grazes in parts of the mudflat in which the surface is known to have a higher concentration of organochlorines
E it digs deeper into the earth and is therefore more likely to encounter toxins- CORRECT (Organochlorines should be  more accessible to long-billed shorebirds that probe deeply for prey  than to short-billed species that forage at or near the surface

3. the author implies that foreign ecosystems have which potential effect on shorebirds?

A They can make a bird more vulnerable to predators.
B They can expose shorebirds to foreign toxins.
C They can diminish a bird’s ability to navigate.
D They can lead to a reduction in the bird’s weight.- CORRECT (A recent study found that, out of those shorebirds that were unable to migrate,  some weighed as much as 20% less than the average  migrating bird of their species)
E They can cause a bird to become separated from its flock.

apovit · Answer

Firstly thanks for starting the RC Butler series  SajjadAhmad  
I have a doubt in question 3:

the author implies that foreign ecosystems have which potential effect on shorebirds? OA D

A They can make a bird more vulnerable to predators.
B They can expose shorebirds to foreign toxins.
C They can diminish a bird’s ability to navigate.
D They can lead to a reduction in the bird’s weight.
E They can cause a bird to become separated from its flock.
 A recent study found that, out of those shorebirds that were unable to migrate, some weighed as much as 20% less than the average migrating bird of their species.
How can we say that the action of unable to migrate lead to a reduction in the weight for the shorebirds.Please explain.
Thanks

auradediligodo · Answer

Hi,

According to me

P1: presentation of a phenomenon "TCH" which is possibly linked to some birds affected by weight loss
P2: evidence that could help find the reason behind the weight loss for a specific category of birds
MP: to present a possible explanation for birds affected by weight loss along with evidence that could explain the reason behind the weight loss

1. The most immediate effect on birds that have accumulated toxins in their fat deposits is

For this question refer to the first part of the first paragraph and especially to:  "For example, large contaminant doses might hamper refueling by altering the satiation signal in shorebirds so that they do not accumulate sufficient fat for migration."

A a tendency to navigate along a divergent flight path -  even tough this could be likely a consequence it is never mentioned 
B an inability to realize when they have eaten a sufficient amount of food -  this seems very in line with what is stated in  the portion of the passage  
C a diminished capacity to retrace their migratory route -  same reasoning for A1 
D an increased likelihood to exhibit aggression towards other species - completely out of scope 
E an increased likelihood to exhibit aggression towards other species -  completely out of scope

2. According to the passage, the long-billed shorebird is expected to be more likely than the short-billed shorebird to have trouble migrating because

For this question refer to the second paragraph and especially to: " Organochlorines should be more accessible to long-billed shorebirds that probe deeply for prey than to short-billed species that forage at or near the surface. "

A it is more vulnerable to the effects of organochlorines -  nowhere it's mentioned that LBS is more vulnerable. It's just more likely to find Organochlorines 
B it typically is unable to differentiate between a foreign ecosystem and a familiar one -  nowhere mentioned. note that foreign ecosystems are mentioned in the previous paragraphs for other reasons 
C it stops feeding before it is fully satiated -  nowhere it is mentioned that it would stop feeding even tough it is likely that it will eat less 
D it grazes in parts of the mudflat in which the surface is known to have a higher concentration of organochlorines - if Organochlorines is in the surface then it is accessible also to SBB hence wrong 
E it digs deeper into the earth and is therefore more likely to encounter toxins -  this is in line with the highlighted portion of the second paragraph

3. the author implies that foreign ecosystems have which potential effect on shorebirds?

for this question refer to the last part of the first paragraph after " a recent study...."
The reasoning here seems to be that a study noticed that some birds weight less than the others and then it is not sure whether the cause is trophic contamination or smith else related to foreign ecosystems. So it would make sense to link foreign ecosystems to weight loss

A They can make a bird more vulnerable to predators. - no mention 
B They can expose shorebirds to foreign toxins. -  it seems that it's either toxins or FE the reason for weight loss not both, hence incorrect 
C They can diminish a bird’s ability to navigate. -  we are concerned to explain the weight loss, hence incorrect 
D They can lead to a reduction in the bird’s weight. -  along the lines of our prethinking 
E They can cause a bird to become separated from its flock. -  we do not know that since it might be just a single bird that is affected by weight loss or many and if many they might stay all together -

Hope this helps,
Any feedback on the reasoning and on paragraph summaries and main point formulation will be much appreciated!

kas007@india.com · Answer

How do we rule out (eliminate) the last option in the last question?

auradediligodo · Answer

We don't know wether just one bird or many birds will be affected by weight loss and if many are affected by weight loss they could still remain together... anyhow this is a very vague answer choice
hope it helps

Pratheek95 · Answer

There is a small with this answer because the satiation criteria is mentioned as an example, hence, we do not know the actual situation, a broader answer mentioned in 'C' seems more appropriate now

Skywalker18 · Answer

All correct except Q3 in 3 mins 45 seconds, including 1 mins 45 seconds to read.

The ‘trophic contamination hypothesis’ posits that shorebirds accumulate industrial and urban pollution at stopover sites, toxins that are subsequently released in sudden high doses as fat is burned during migratory flights, disrupting the bird’s ability to make migratory decisions.

or whether such birds simply cut their migrations short by landing in a  foreign ecosystem , is unlikely to be resolved until further studies are conducted.

3. the author implies that foreign ecosystems have which potential effect on shorebirds?

A They can make a bird more vulnerable to predators.- incorrect, predators are not discussed
B They can expose shorebirds to foreign toxins.- incorrect, foreign toxins are not discussed
C They can diminish a bird’s ability to navigate.- incorrect, the foreign ecosystems by itself does not cause this phenomenon
D They can lead to a reduction in the bird’s weight.
E They can cause a bird to become separated from its flock.

I wasn't happy with any of the answers and chose option E at last(using POE). 
 Are stopover sites same as foreign ecosystems?

AjiteshArun  ,  GMATNinja  ,  MagooshExpert  ,  GMATGuruNY  ,  VeritasPrepBrian  ,  MartyTargetTestPrep  ,  DmitryFarber  ,  VeritasKarishma  ,  generis  , other experts - please enlighten

nityakaul02 · Answer

what is the difficulty level of each question ?

Sajjad1994 · Answer

Question #1: 700
Question #2: 650
Question #3: 700

Good Luck

Jamiul · Answer

Hello,
 Pls clear my doubt: The first sentence says"The ‘trophic contamination hypothesis’ posits that shorebirds accumulate industrial and urban pollution at stopover sites, toxins that are subsequently released in sudden high doses as fat is burned during migratory flights, disrupting the bird’s ability to make migratory decisions."

Now, does it mean: The Trophic theory suggests that, at atopover sites, shorebirds accumulate industrial and urban pollutants, these pollutants are latter ejected in high doses as fat is burned during migratory flights, and intake of these toxic pollutants disrupt the bird’s ability to make migratory decisions. ??

If my above explanation is right, then, i think the sentence can be rearranged in a bit different way:

The ‘trophic contamination hypothesis’ posits that shorebirds accumulate industrial and urban pollution at stopover sites, toxins that are subsequently released in sudden high doses as fat is burned during migratory flights, disrupting the bird’s ability to make migratory decisions.

MayankDimri · Answer

Hi Sajjad,

Can you please official explanation for Q3?

Thanks

Sajjad1994 · Answer

OE is not available; read the explanation to question #3 in the post in the link below https://gmatclub.com/forum/the-trophic- ... l#p2231621 Thank you!

Sajjad1994 · Answer

Finally found one for you.

Official Explanation

3. the author implies that foreign ecosystems have which potential effect on shorebirds?

Difficulty Level:   700

Explanation

The fact that some birds were 20% lighter than other birds can either be explained by contamination or by a foreign ecosystem. Therefore, the author implies that foreign ecosystems can result in a loss of weight. Answer (D).

(A)  is out since there is no mention of predators.

(B)  is tempting but remember the bird is exposed to toxins in its usual habitat.

(C)  is out. It is the toxins, not the foreign ecosystems that can diminish a bird’s ability to migrate.

(E)  is not supported by the passage.

Answer: D

Sajjad1994 · Answer

Official Explanation

2. According to the passage, the long-billed shorebird is expected to be more likely than the short-billed shorebird to have trouble migrating because

Difficulty Level:   600-650

Explanation

(E)  is supported by,  “Organochlorines should be more accessible to long-billed shorebirds…near the surface.”  That is the long-billed shorebird has a longer beak so it naturally reaches a deeper part of the ground. The problem, at least for the long-billed bird, is that organochlorines are present deeper in the soil.

(A)  is not supported by the passage.

(B)  and  (C)  relate to different parts of the passage, but do not answer the question.

(D)  is tempting, but remember that it is not the part of the mudflat with more toxins at the surface that lead to the long-billed shorebird’s exposure to toxins. What accounts for the long-billed shorebird's exposure to toxins is that it digs deeper than the short-billed shorebird.

Answer: (E)

Sajjad1994 · Answer

Official Explanation

1. The most immediate effect on birds that have accumulated toxins in their fat deposits is

Difficulty Level:   700

Explanation

According to the  second sentence in the first paragraph ,  “For example, large contaminant doses might hamper refueling by reducing the satiation signal in shorebirds so that they do not accumulate sufficient fat for migration.”  Another way of saying this is that the birds cannot determine when they’ve eaten enough. This inability results in birds not having enough fat for migration. Therefore,  (B).

(A)  is tempting, but notice the phrase in the question  “most immediate effect”. (A)  is likely to result but according to the passage does not always result in a bird suffering from  “trophic contamination hypothesis”.

(C)  is never really mentioned, since we don’t learn about the bird’s inability to retrace its path. We do learn that it may end up in a foreign ecosystem, but inferring that such birds are unable to retrace their routes is inferring too much. Also, the phrase  “migratory decisions”  is a little too vague and is not necessarily the same as an ability to retrace a migratory route.

(D)  There is no mention of aggression to other species, so  (D)  is out.

(E)  is tempting but the passage does not say that the toxins cause fat deposits to decrease. Rather, fat deposits, when they are burned during flight, release the toxins and, consequently, the birds ability to make migratory decisions is affected.

Answer: B

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The ‘trophic contamination hypothesis’ posits that shorebirds accumula

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