The West Indian manatee, a distant relative

[igordudchenko]

Please explain the reasoning behind the OA?
+++
The West Indian manatee, a distant relative of the elephant, returned to the sea some 50 million years ago. These thousand-pound herbivores inhabit the warm coastal waters where Americans like to play. Despite conservation efforts, criminal penalties for harming these creatures, and an overabundance of SAVE THE MANATEE! bumper stickers, none of these animals can be considered safe.

Which of the following, if true, most strongly supports the argument above?

a) Last year, several manatees were mysteriously killed by an unidentified toxin.
b) All manatees swim at depths that make them vulnerable to the blades of motorboat engines.
c) Most tourists are unaware of the ongoing efforts to save the manatee.
d) The population of manatees in the wild has dwindled to fewer than 2,500 animals.
e) Although dozens of manatee deaths are documented each year, many more deaths go unreported.
----
I was choosing between A and B. I assumed since conservation is in place, some of the animals will be excluded from the contact with motor boats, so B is not that relevant.
In contrary, if there is a killing toxin and nothing is done (according to the text) to prevent its action, it will eventually kill the animals.

OA is B!

[goal.ambitions]

Is the OA A?

[mithilesh.vnit85]

Hi,

Is OA E?

[tim]

The big difference between B and A is that in A *some* of the animals are clearly in trouble, but in B *all* of the animals are potentially in danger. Therefore B is the only one that supports the contention that none of the animals are safe. Does this help?

[jp.jprasanna]

The big difference between B and A is that in A *some* of the animals are clearly in trouble, but in B *all* of the animals are potentially in danger. Therefore B is the only one that supports the contention that none of the animals are safe. Does this help?

Thanks a lot tim for your explanation. It does indeed help.

So in GMAT Several = Some always? - Takeaway?

[tim]

that's a very narrow takeaway, but if you want to bother memorizing something i'd say the more accurate statement is that "several" conveys something less than "all". this should be self-evident though..

[suyash.tiwari]

What's wrong with C ?
Since most tourists are not aware of the efforts,they might be careless towards the Manantees and hence might be killing them in large number ?

Instructors ?

[jnelson0612]

What's wrong with C ?
Since most tourists are not aware of the efforts,they might be careless towards the Manantees and hence might be killing them in large number ?

Instructors ?

Possibly, but that's a stretch. The fact that tourists are unaware may also have little impact on the manatees. Note that the questions asks which answer choice most *strongly* supports the conclusion that "no manatees can be considered safe". I put my comments below in blue:

b) All manatees swim at depths that make them vulnerable to the blades of motorboat engines.Thus, every single member of the manatee population is at risk of being hit by motorboat blades. This seems to support the idea that no manatees can be considered safe.

c) Most tourists are unaware of the ongoing efforts to save the manatee. Does this really matter? Even if the tourists don't know that there is a campaign to save the manatee, will they harm the manatees? Do we know that it is tourist activity that damages the manatee in the first place? Maybe it's more from the locals.

Also, let's say the tourists are harming the manatees the most. Would the tourists change their behavior if they KNEW that there was a campaign to save the manatees? We don't know. B is just a stronger answer at supporting the conclusion.

[jejimenp]

Hi, i still don't get this question.

If B is the right choice then you would have to assume that there are actually lots of people going arround in motorboats in order to assume that all manatees are in danger.
I don't understand why you can assume that and not that the toxin is a potencial danger to all manatees.

[jnelson0612]

Hi, i still don't get this question.

If B is the right choice then you would have to assume that there are actually lots of people going arround in motorboats in order to assume that all manatees are in danger.
I don't understand why you can assume that and not that the toxin is a potencial danger to all manatees.

Well, the problem does say "warm coastal waters where Americans like to play". I think that the GMAT test writers would say that it's reasonable to infer that Americans are "playing" by doing what they typically do in "warm coastal waters": swimming, surfing, and using boats.

Regarding answer A, I'm also going to repost what Tim said about A vs. B, because his point is well made: "The big difference between B and A is that in A *some* of the animals are clearly in trouble, but in B *all* of the animals are potentially in danger. Therefore B is the only one that supports the contention that *none* of the animals are safe."

I would just add to Tim's explanation that the toxin has killed "some" manatees. It may just be that certain manatees are naturally susceptible and others are immune to the toxin. For "none" of the manatees to be safe I have to have some threat that can potentially harm every single manatee. Just knowing that a toxin has killed "some" is not a big enough threat. "Some" may be as few as two or three.

[milindshastri]

Hi, i still don't get this question.

If B is the right choice then you would have to assume that there are actually lots of people going arround in motorboats in order to assume that all manatees are in danger.
I don't understand why you can assume that and not that the toxin is a potencial danger to all manatees.

Well, the problem does say "warm coastal waters where Americans like to play". I think that the GMAT test writers would say that it's reasonable to infer that Americans are "playing" by doing what they typically do in "warm coastal waters": swimming, surfing, and using boats.

I am pretty confused here. Isn't the assumption that playing in the waters is the same as going around in motor boats which have blades. Like you said, there are lots of ways of playing in the waters: jet-skiing, surfing, paragliding, swimming, snorkeling, rowing and perhaps some sort of motor-boating without blades just to name a few. So people could very well be playing all day long without a single motorboat with blades even touching the waters. Its confusing to me why it seems that *all* manatees are at risk here since only manatees in the path of motorboats with blades, if any, are at risk.

In that case, I am wondering if the toxin killing the manatee in option A) could be assumed to be a water toxin (just like all playing is assumed to be motorboats+blades+motorboats running over manatees) which is present in the water that manatees swim in. Hence all manatees are susceptible to the toxic. Hence, none of the manatees can be considered safe despite the conservation efforts because all those efforts mentioned are non-toxin related.

:/

[RonPurewal]

I am pretty confused here. Isn't the assumption that playing in the waters is the same as going around in motor boats which have blades.

nah. you just have to read the words more carefully than you're currently reading them.

that answer choice says ...
All manatees swim at depths that make them vulnerable to the blades of motorboat engines

so,
* we know that it's all manatees,
and
* we know that all of them have a nonzero chance of being cut by the blades, since that's implied by the meaning of the word "vulnerable".

[maizuka]

Hi, i still don't get this question.

If B is the right choice then you would have to assume that there are actually lots of people going arround in motorboats in order to assume that all manatees are in danger.
I don't understand why you can assume that and not that the toxin is a potencial danger to all manatees.

Well, the problem does say "warm coastal waters where Americans like to play". I think that the GMAT test writers would say that it's reasonable to infer that Americans are "playing" by doing what they typically do in "warm coastal waters": swimming, surfing, and using boats.

I am pretty confused here. Isn't the assumption that playing in the waters is the same as going around in motor boats which have blades. Like you said, there are lots of ways of playing in the waters: jet-skiing, surfing, paragliding, swimming, snorkeling, rowing and perhaps some sort of motor-boating without blades just to name a few. So people could very well be playing all day long without a single motorboat with blades even touching the waters. Its confusing to me why it seems that *all* manatees are at risk here since only manatees in the path of motorboats with blades, if any, are at risk.

In that case, I am wondering if the toxin killing the manatee in option A) could be assumed to be a water toxin (just like all playing is assumed to be motorboats+blades+motorboats running over manatees) which is present in the water that manatees swim in. Hence all manatees are susceptible to the toxic. Hence, none of the manatees can be considered safe despite the conservation efforts because all those efforts mentioned are non-toxin related.

:/

I have to agree with milindshastri. I think that both A and B have to assume something that is not written on the question. And I don´t see why is OK to assume that Americans playing is equal to boats with blades but not OK to assume that a toxin is dangerous to the whole species.

[jnelson0612]

Everyone, I don't know what else the three of us can do to make this more clear, now that Tim, Ron, and I have all weighed in.

Answer choice A says that some manatees died from the toxin. I cannot logically conclude from that that ALL manatees are at risk. I just don't know that. It may be that only some are susceptible to the toxin.

On the other hand, if every single manatee is at risk of getting run over by a boat, then ALL manatees are at risk.

[ishanbhat455]

Everyone, I don't know what else the three of us can do to make this more clear, now that Tim, Ron, and I have all weighed in.

Answer choice A says that some manatees died from the toxin. I cannot logically conclude from that that ALL manatees are at risk. I just don't know that. It may be that only some are susceptible to the toxin.

On the other hand, if every single manatee is at risk of getting run over by a boat, then ALL manatees are at risk.

Hi Jamie,

I see another fault with option B. It talks about the danger of blades to the manatees swimming at a certain depth. The argument talks about conservation efforts being in place, and the manatees still not safe. Does that not place a doubt on the conservation efforts in the first place? Why are the boats allowed in the warm coastal waters if these boats harm the manatees? To me, option B looks more like a weakener rather than a strengthener because it attacks the basis (i.e- conservation efforts) of the claim.

Let me know what you think about this perspective.

Thanks,
Ishan