A major chemical spill occurred five years ago at Baker’s Be

[JbhB682]

Source : GMAT prep

A major chemical spill occurred five years ago at Baker’s Beach, the world’s sole nesting ground for Merrick sea turtles, and prevented nearly all the eggs laid that year from hatching. Yet the number of adult female Merricks returning to lay their eggs at Baker’s Beach has actually increased somewhat since five years ago. Clearly, environmentalists’ prediction that the world’s Merrick population would decline as a result of the spill has proven unfounded.

Which of the following, if true, most seriously undermines the argument offered in refutation of the environmentalists’ prediction?


A. The chemical spill five years ago occurred at a time when there were neither Merrick sea turtles nor Merrick sea turtle eggs on Baker’s Beach.

B. Female Merrick sea turtles begin returning to Baker’s Beach to lay their eggs when they are ten years old.

C. Under normal conditions, only a small proportion of hatchling female Merrick sea turtles survive in the ocean until adulthood and return to lay their eggs at Baker’s Beach.

D. Environmental pressures unrelated to the chemical spill have caused a significant decline in the population of one of the several species of sea birds that prey on Merrick sea turtle eggs.

E. After the chemical spill, an environmental group rejected a proposal to increase the Merrick sea turtle population by transferring eggs from Baker’s Beach to nearby beaches that had not been affected by the spill.

[JbhB682]

GMAT prep problem : https://ibb.co/X8bR5w8

[JbhB682]

Hi Experts - i thought D was a weakener regarding the argument.

Argument : we see more turtles returning to hatch eggs. Thus the prediction (Regarding overall population decline) is wrong

D suggests predators of turtles have declined.

THAT is the reason for why there are more female turtles seen for nesting (because more turtles are surviving now, given the turtles' predator has declined in number)

This weakens the author's claim that just because more turtles are returning to hatch eggs, the oil spill COULD NOT have caused reduced populations

[TiffanyB]

Hello JBHB682,

In CR, it helps to break down the argument thoroughly and then state your goal very clearly.

Analysis of the argument:

Chemical spill at Baker's Beach 5 years ago

Baker's Beach = Merrick sea turtles ONLY nesting ground

Nearly all eggs laid that year were prevented from hatching

HOWEVER the # of adult females (what about males?) returning to lay eggs at Baker's Beach has increased (somewhat? how much is that?) since 5 years ago

The author seems to believe, based on observations, that the Merrick sea turtle population has not declined, as environmentalists had predicted.

GOAL: Undermine (Weaken) the author's stance that environmentalists' predictions about the decline of Merrick sea turtles due to the oil spill are unfounded.

Note: This problem is tricky because we're undermining / weakening, but there are two stances: the author's and the environementalists'. We need to weaken the author's stance, which is the one "offered in refutation of the environmentalists' prediction."

----------------------------
A major chemical spill occurred five years ago at Baker’s Beach, the world’s sole nesting ground for Merrick sea turtles, and prevented nearly all the eggs laid that year from hatching. Yet the number of adult female Merricks returning to lay their eggs at Baker’s Beach has actually increased somewhat since five years ago. Clearly, environmentalists’ prediction that the world’s Merrick population would decline as a result of the spill has proven unfounded.

Which of the following, if true, most seriously undermines the argument offered in refutation of the environmentalists’ prediction?


A. The chemical spill five years ago occurred at a time when there were neither Merrick sea turtles nor Merrick sea turtle eggs on Baker’s Beach. Strengthen. Environmentalists' predictions were unfounded.

B. Female Merrick sea turtles begin returning to Baker’s Beach to lay their eggs when they are ten years old. Weaken. If they return when they are 10 years old, we will not see a reduction in returning females until 10 years after the oil spill, when the hatchlings born then would have been returning.

C. Under normal conditions, only a small proportion of hatchling female Merrick sea turtles survive in the ocean until adulthood and return to lay their eggs at Baker’s Beach. No impact to argument. Author is saying that predictions of decline due to oil spill were unfounded. This doesn't help us analyze impacts of the oil spill on the turtle population.

D. Environmental pressures unrelated to the chemical spill have caused a significant decline in the population of one of the several species of sea birds that prey on Merrick sea turtle eggs. Strengthen. This helps the author's argument that the environmentalists' concerns were unfounded by giving an explanation about why more turtles than expected may have survived despite the oil spill.

E. After the chemical spill, an environmental group rejected a proposal to increase the Merrick sea turtle population by transferring eggs from Baker’s Beach to nearby beaches that had not been affected by the spill. No impact to author's argument. The author is basing their conclusion (predictions of population decline are unfounded) on observations of female Merricks. This answer choice doesn't change what the author observed.

[JbhB682]

Thanks so Much Tiffany. Two quick questions

(Q1) Do you think the argument by the author is essentinally in the format -- If X, then Y (Y is true or Y is implied)

[JbhB682]

Q2)

Same option D but with a small change, let say (option D1)

(option D1)
Environmental pressures unrelated to the chemical spill have caused a significant **INCREASE** in the population of one of the several species of sea birds that prey on Merrick sea turtle eggs.

I think this would be a wash

Because the premise is still saying 'adult female Merricks" are returning in higher numbers.

So, even if predation on Merrick Sea Turtle eggs is happening MORE -- it is 'baked' into the premise that 'adult female Merricks" are returning in higher numbers.

So -- its a 'wash'

Thoughts ?

[abaltao1]

Hi Experts - i thought D was a weakener regarding the argument.

Argument : we see more turtles returning to hatch eggs. Thus the prediction (Regarding overall population decline) is wrong

D suggests predators of turtles have declined.

THAT is the reason for why there are more female turtles seen for nesting (because more turtles are surviving now, given the turtles' predator has declined in number)

This weakens the author's claim that just because more turtles are returning to hatch eggs, the oil spill COULD NOT have caused reduced populations

Why E variant is wrong? Can you explain, please?

[Whit Garner]

Thanks so Much Tiffany. Two quick questions

(Q1) Do you think the argument by the author is essentinally in the format -- If X, then Y (Y is true or Y is implied)

I love that you're trying to think of the underlying form of the argument. That said, I would say that the underlying argument format for the vast majority of Critical Reasoning questions could be put into the form of "If X, then Y": if everything we just told you in the argument is true, then ______ is our conclusion.

[Whit Garner]

Why E variant is wrong? Can you explain, please?

Same option D but with a small change, let say (option D1)
(option D1)
Environmental pressures unrelated to the chemical spill have caused a significant **INCREASE** in the population of one of the several species of sea birds that prey on Merrick sea turtle eggs.

For these questions, it might be useful to spend some extra time on this problem unraveling the double-negative in the question: you're being asked to "weaken" a "criticism" - in other words, to weaken a weaken. Does that mean we're strengthening something?? (so confusing)

First, the environmentalists think turtles populations have declined because an entire year's babies weren't born.
But critics disagree: "here we are a year later and look at all of these turtles - turtles are fine!"
I'm supposed to attack/weaken that... "how do we lose a year of turtles and don't see it show up in the numbers??"

GOAL: There must be SOMETHING hiding the decline from us, that's what I'm looking for!
note that I abandoned the words "weaken" or "strengthen" as it often makes me more confused. I wanted to focus on what the answer choice needed to do

Now let's go after the answer again, because I have a slightly different attack than before:

A. The chemical spill five years ago occurred at a time when there were neither Merrick sea turtles nor Merrick sea turtle eggs on Baker’s Beach.
Wait, how is this even allowed to be true?? we were told that this beach is the only place they nest AND that the chemical spill prevented most of the eggs from hatching. This contradicts facts we were given so throw it out!

B. Female Merrick sea turtles begin returning to Baker’s Beach to lay their eggs when they are ten years old.
The critics claimed that all of these momma turtles came back the year after the spill. How could their age be hiding the decline? I don't eliminate answer choices just because they're confusing; leave it for now.

C. Under normal conditions, only a small proportion of hatchling female Merrick sea turtles survive in the ocean until adulthood and return to lay their eggs at Baker’s Beach.
Life at sea is tough for the turtles, okay, but that's always the case according to this. We still saw a larger number than normal come back post spill. I want to show that a decline (from the norm) is still possible, this isn't helping me do that."

D. Environmental pressures unrelated to the chemical spill have caused a significant decline in the population of one of the several species of sea birds that prey on Merrick sea turtle eggs.
This would indicate that things might be looking up for the turtles! Good for the turtles, but bad for me - I'm trying to show that the turtles are declining (in spite of seeing more of them)! Okay, but what about the suggested change to [color=#FF0000]INCREASE? It would mean that our poor turtles are back in trouble again. Man, they really can't catch a break can they. BUT, the argument hinges on the idea that seeing MORE means the turtles are fine and we should stop worrying. That means that our right answer needs to address how seeing MORE turtles is actually fooling us - we see more, but there are actually fewer (how is the decline being hidden)..." [/color]

E. After the chemical spill, an environmental group rejected a proposal to increase the Merrick sea turtle population by transferring eggs from Baker’s Beach to nearby beaches that had not been affected by the spill.
Okay, so this group has decided not to help out, which means that the oil spill still sounds bad for our poor sea turtles. But just like the edited version of D - this certainly makes me worried for our poor sweet swimmers, BUT it doesn't address the real concern - how are we seeing more when there are actually less - what is hiding the decline from us??

Right now, I'd be looking at a paper with ACDE all eliminated. So I'd be picking B. But let's confirm why. According to (B), sea turtles have to grow up quite a bit before they start coming home. So the generation of turtles we lost (thanks to the stupid oil spill) wouldn't have been returning for a decade; we won't know that there really is a "lost generation" until then. For now, we're seeing the generations of sea turtles born at least 10 years ago (well before the oil spill). This would help explain how we see more turtles now, but that the overall numbers are dwindling! Essentially - ya'll just wait, we'll see those declined numbers in about 10 years!

Hope this helps!