Some species of Arctic birds are threatened by recent sharp increases

Some species of Arctic birds are threatened by recent sharp increases in the population of snow geese, which breed in the Arctic and are displacing birds of less vigorous species. Although snow geese are a popular quarry for hunters in the southern regions where they winter, the hunting season ends if and when hunting has reduced the population by five percent, according to official estimates. Clearly, dropping this restriction would allow the other species to recover.

Which of the following, if true, most seriously undermines the argument?

(A) Hunting limits for snow geese were imposed many years ago in response to a sharp decline in the population of snow geese.
(B) It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date.
(C) The number of snow geese taken by hunters each year has grown every year for several years.
(D) As their population has increased, snow geese have recolonized wintering grounds that they had not used for several seasons.
(E) In the snow goose’s winter habitats, the goose faces no significant natural predation.

Start with the conclusion: dropping the restriction (that ends the snow geese hunting season if and when hunting has reduced the population by 5%) would allow other (less vigorous) bird species to recover. Before diving into the answer choices, make sure you understand the structure of the author's argument... how does the author arrive at that conclusion?

• Recently, there have been sharp increases in the population of snow geese, which breed in the Arctic.
• The snow geese are displacing birds of less vigorous Arctic bird species and thus threatening those species.
• Snow geese spend their winters in the southern regions, where they are popular targets for hunters.
• The snow geese hunting season is currently restricted. Once hunting has reduced the snow geese population by 5%, the hunting season ends (hunters are no longer allowed to hunt at that point).
• The author believes that ending that restriction would allow the threatened species to recover. In other words, even if hunting reduces the snow geese population by 5%, hunters should be allowed to continue hunting and reduce the population even further.

Now that we understand the argument, we need an answer choice that undermines that argument:



It doesn't matter WHY the restrictions were implemented. We are trying to determine whether eliminating those restrictions would help the threatened bird species. Furthermore, choice (A) suggests that the snow geese population DECREASES when there are no hunting restrictions. This is exactly what the author hopes will happen. If the restrictions are eliminated, the snow geese population will decrease, helping the threatened species to recover. Choice (A) actually strengthens the author's argument and should be eliminated.



The restriction only goes into effect once hunting has reduced the population by 5%. Since the restriction hasn't actually been used in many years, this tells us that hunting hasn't led to a 5% reduction in that time. If the restriction were removed, hunting levels would probably not increase, and the snow geese population would not be reduced.

In other words, the author says, "hey, currently hunters can only reduce the population by 5%... let's remove that restriction so that they can reduce the population even further." But if hunters currently only reduce the population by LESS than 5%, there is no reason to believe that removing the restriction will have any effect. Even if the restrictions are removed, hunting will still probably only reduce the population by less than 5%. Thus, removing the restriction would not have the effect suggested by the author, weakening the argument. (B) looks good.



If the snow geese population is increasing faster than the number hunted each year, the population will still continue to grow. For example, if the number taken increases by 100 each year but the population increases by 1,000 each year, then the overall population will still increase by 900 each year. That would validate the problem described by the author and would not hurt the argument. Furthermore, we are already told that the snow geese population has been increasing sharply, so (C) doesn't help us.



This might suggest that the hunters will not be able to get to the snow geese in those recolonized areas. However, that doesn't significantly impact the author's reasoning. According to the author, if we remove the restriction, hunters in the southern regions will be able to hunt more geese and reduce their population by more than 5%. Choice (D) might suggest that the SG population might get out of control if action is not taken soon. Still, theoretically, if hunters can significantly reduce the population in the southern wintering regions, the SG population would likely be curtailed. Eliminate (D).



We are trying to determining whether eliminating HUNTING restrictions will affect the snow geese population. Choice (E) is irrelevant and can be eliminated.

(B) is the best answer.

Clear B

A.Hunting limits for snow geese were imposed many years ago in response to a sharp decline in the population of snow geese.
- supports the argument

B.It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date.
- hunters normally do not hunt more than 5% of the population. So, removing the restriction is not going to increase the number of snow geese hunted during winter. WEAKENS the argument.

C.The number of snow geese taken by hunters each year has grown every year for several years.
- we already know that population is increasing, so number of birds constituting 5% will also have increased. Does not add anything.

D.As their population has increased, snow geese have recolonized wintering grounds that they had not used for several seasons.
- irrelevant.

E.In the snow goose’s winter habitats, the goose faces no significant natural predation.
- irrelevant.

I went with B. Here is my explanation -

The argument is that the 5% restriction needs to be dropped in order for people to be able to hunt more geese, thus reducing their population. If for the last several years that 5% limit has never been reached, that means hunters aren't able to kill enough geese within the full hunting season (because the population now is so large), dropping the restriction would have no effect to the population.

Hope this helps.

It's a weaken question. The golden rule is to focus on the conclusion and try to weaken it.
What is the conclusion here? " Clearly, dropping this restriction would allow the other species to recover."

You have to try to weaken it i.e. give reasons why even after dropping this restriction, it is unlikely that other species will recover.

(B) It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date

Option B tells you that the restriction doesn't really matter much. It has been many years since the restriction led to the hunting season closing down early. This means that the population of geese is enough so the restriction hasn't come into effect in the recent years. This implies that even if the restriction is removed, it is likely that there will be no change in the situation. This definitely weakens our conclusion that dropping the restriction will help other species to recover.

Snow geese breed in Arctic and fly south for winter. They are proliferating which is bad for other birds. Southern hunters reduce the number of geese when they fly south. There is a restriction in place that if the population of the geese that came reduces by 5%, hunting will stop. So if 100 birds flew south and 5 were hunted, hunting will stop. If 1000 birds flew south and 50 were hunted, hunting will be stopped. The argument says that we should drop this restriction to help other birds flourish (conclusion). Then hunters will hunt many more birds and reduce their numbers. Then the other Arctic birds will flourish.

We need to weaken it and say that dropping the restriction will not help other Arctic birds flourish. Even if this restriction of 'not hunting after 5%' is dropped and hunters are allowed to hunt as much as they want, the population of geese will still not reduce.

(B) says that the it has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date. This means that for many years, the 5% limit has not been reached. So southern hunters anyway hunt less than 50 birds when 1000 birds fly down south. So whether you have the restriction or not, the number of geese hunted is the same. Usually hunters hunt less than 50 birds. So even if you drop the restriction and tell them that they can hunt as much as they want, it will not help since they don't want to hunt much. They usually hunt only a little bit. So the geese population will not reduce by dropping this restriction.

(D) is not correct.
"wintering grounds" implies the southern region (where they fly for winter). In south, they have re-colonized regions they had not occupied for a while now. This doesn't imply that dropping the restriction and letting hunters hunt as much as they want to will not decrease their population. The hunters hunt in the southern region. Nothing says they don't hunt in the regions where the geese have recolonized now.

Understand the argument: Snow geese populate the Arctic (i.e. the north pole region) and are displacing other species there. They move south in winters where there numbers are reduced due to hunting. There are restrictions on hunting. The argument says 'remove these restrictions so that the number of geese reduces more so that other species can survive. Saying that geese are recolonizing larger parts of the southern region doesn't imply that dropping restrictions will not help.

In fact, if anything, it may make the argument a little stronger. If the geese are occupying more southern areas, hunting grounds may become easily accessible to more hunters and dropping hunting restrictions may actually help more!

Conclusion:
Clearly, dropping this restriction would allow the other species to recover.

Reasoning:
Here's a causal reasoning in that dropping the hunting restriction would allow the other species [arctic birds] to recover. Thus, any other claim that disproves the relationship works. Look for: 1) alternative causes 2) no cause -> effect 3) cause -> no effect 4) reverse relationship 5) undermining data.

(A) Hunting limits for snow geese were imposed many years ago in response to a sharp decline in the population of snow geese. Opposite answer - Strengthen. If hunting limits were imposed + hunting has reduced population over five percent, then dropping the restriction would likely allow the other species to recover.

(B) It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date. OK - This weakens the conclusion in that if the cause happened [dropping the restriction had occurred], then there would be no effect [species would not have recovered] (because there's already too many geese).

(C) The number of snow geese taken by hunters each year has grown every year for several years. Opposite answer - Strengthen. If the number of snow geese taken by hunter has grown + a sharp increase in snow geese are displacing bird of less vigorous species, then dropping the restriction would allow the other species to recover. A lot of different nouns to keep track of makes this choice confusing.

(D) As their population has increased, snow geese have recolonized wintering grounds that they had not used for several seasons. Out of scope. Whether or not the snow geese had the grounds before the Arctic birds, the main claim still stands that dropping the hunting restriction would help.

(E) In the snow goose’s winter habitats, the goose faces no significant natural predation. Opposite answer - Strengthen. If the snow geese had no natural predation, then dropping the restriction would allow the other species to recover.

Actually (C) is not correct.

It's a weaken question. The golden rule is to focus on the conclusion and try to weaken it.
What is the conclusion here? " Clearly, dropping this restriction would allow the other species to recover."

You have to try to weaken it i.e. give reasons why even after dropping this restriction, it is unlikely that other species will recover.

(B) It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date

Option B tells you that the restriction doesn't really matter much. It has been many years since the restriction led to the hunting season closing down early. This means that the population of geese is enough so the restriction hasn't come into effect in the recent years. This implies that even if the restriction is removed, it is likely that there will be no change in the situation. This definitely weakens our conclusion that dropping the restriction will help other species to recover.

(C) The number of snow geese taken by hunters each year has grown every year for several years.

(C) doesn't tell us how dropping the restriction would impact the geese population. It just tells us what has happened in the past - the number of geese hunted has been increasing. If anything, it might strengthen our conclusion if the number of geese hunted is close to 5% of the population. When the population decreases by 5%, if the restriction is dropped, chances are that more geese will be hunted and other species will recover. We have to show how even after dropping the restriction, the other species may not recover.

Say the hunting season is from 1st Dec to 28th Feb. It closes early if population decreases by 5%.

(B) It has been many years since that limit has reached
means for many years that limit has NOT been reached (I think you misunderstood option (B))
So option (B) is telling you that the rule has NO impact since the 5% limit anyway is not reached.

Hi PrakharGMAT,

The conclusion says that if we lift the restrictions the population of arctic birds will increase as snow geese feeds on it.
Th restriction on hunting snow geese comes into effect when their population has gone down by 5%, that is 5% snow geese have been killed..

what does B say--
(B) It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date.

It tells us that restriction came into play long time back, meaning the hunters have never hunted a % touching 5%.
If this restriction is lifted, the numbers hunted will not go up as the threshold % -5%- has never been reached..
So, it can be assumed that if hunters continue hunting at the same pace with or without restrictions, there will be no change in the decrease of arctic birds

Scheduled date here means WINTER..
the hunting is allowed in WINTERS, so there is a specific date at the end of winters every year, when the hunting has to stop. It will stop prior to this date if the % hunted that year has gone upto5%...

Hi chetan2u,

Thanks for your response. I hope, I got the point
Let me explain what I got with an example and please correct me if I am wrong.

(B) It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date.


At present we are in 2016, but option B says that restriction on hunting season was imposed LONG TIME BACK lets say in 2000.
Means in 2000 hunters touched the limit of 5% and hence the restriction was imposed.
But if we talk about period 2000 - 2016 hunters haven't touched the figure of 5% and hence the restriction has not been imposed..
So, lifting restriction will NOT help---> ARGUMENT WEAKENED

I hope that's all the story.

Can you please share your opinion..?
Thanks

Hi,
You are absolutely correct now.
From last 16 years, the restriction was or rather could not be imposed due to the hunting not reaching 5%.

Posted from my mobile device

The most difficult question i have encountered.
Wording in option B makes it eeven more trickier for one to understand what the option actually conveys.
I misunderstood option B .

My interpretation was - As restriction imposed on hunting is closed earlier than scheduled date , limit of 5% is actually achieved way before the hunting season ends. And thus is strengthening the argument.

Basis the various discussions posted for this question , what i understand from option B -- " It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date." is - key lies in the words" It has been many years since " - author says- its been many years since restriction is imposed , where this restriction has led to closure of hunting season earlier than scheduled. . Restriction never came into play only.


Can anyone help me if my understanding is right . GMATNinja VeritasKarishma chetan2u

Yes, you are absolutely correct when you say that the words ‘ it has been many years since...’ make the option a weakener and means that the restriction has almost no role to play in the closure of hunting season. The hunting has never, for a long time now, resulted in the drop of population by more than 5%.

GMATNinja VeritasKarishma

I interpreted B in a very different way from what you guys have suggested. Here's what I inferred from B:



The restriction has not come into effect for a long time. This means that hunters have not reached the 5% threshold anyway. Now, hunters might not have reached the 5% threshold DELIBERATELY, because they knew that such restrictions are there. Basically, if they reach 5% threshold, hunting season will end. So, they are being very cautious of the excessive hunting.

But, if the restrictions are removed, there is no fear at all anyway. So what held true earlier might not hold true in this case. Because restrictions are not there, there do not have to worry about 5% threshold. They can go all in and hunt as much as they want. So, the condition that pulled back their behaviour is gone. In new paradigm, they will hunt more and the snow geese population will dwindle.

saman283 - I understand your concern and appreciate your belief in people's sense of logical reasoning.
But all said and done, it's a conjecture and has no basis in what is given. All we know is that it has not reached 5% in a long time so people are not hunting that much. It is highly unlikely that the officials run a public counter informing the people of the numbers reached for people to know whether they should hunt or not. The argument does not suggest it. Hence, you need to take option (B) on face value.

Thanks for the reply, VeritasKarishma. I often get in trouble with CR because sometimes I think too deep and sometimes not deep enough.

Do you have any suggestions for me through which I can improve my accuracy on CR?