Knewton Verbal Challenge Question: Critical Reasoning

Question

Hi all!

Knewton is starting a new challenge series within the GMAT Club forums -- each week, we'll post an extra-hard challenge question to help you test your skills. This week, try your hand at this tough CR question. 67.6% of Knewton students got this one wrong. Will you beat the odds?

Reply with your answers, questions, and thought processes below. We'll post a video explanation in a few days to let you know how you fared.

Good luck!

A newborn kangaroo, or joey, is born after a short gestation period of only 39 days. At this stage, the joey’s hind limbs are not well developed, but its forelimbs are well developed, so that it can can climb from the cloaca into its mother’s pouch for further development. The recent discovery that ancient marsupial lions were also born with only their forelimbs developed supports the hypothesis that newborn marsupial lions must also have needed to climb into their mothers’ pouches.

The argument in this passage relies on which of the following assumptions?

All animals that are born after a short gestation period are born with some parts of their bodies underdeveloped.
   Well developed forelimbs would have been more advantageous to ancient marsupial lions than well developed hind limbs would have been.
   If the newborn marsupial lion did not climb into its mother’s pouch, then paleontologists would be able to find evidence of this fact.
   Newborn marsupial lions that crawled into their mothers’ pouches could not have done so had they not had only their forelimbs developed at birth.
   Newborn marsupial lions would not have had only their forelimbs developed if this development were of no use to the marsupial lions.

wininblue · Answer

Hi Chris,

Tough one! I think OA is  E

Thought process:
This passage relies on drawing a conclusion based on analogy. 2 facts are : how forelimbs help Joeys - similarly forelimbs may also help baby Lions.
So the assumption has to be something that fills the gap between the fact and the conclusion.

mailnavin1 · Answer

E it is. I had seen this q somewhere

akshathbs · Answer

conclusion :: since M- lions have their forelimbs developed they have to climb into their mother's pouch

since this is an assumption question use assumption negation technique::
option a)All animals that are born after a short gestation period are not born with some parts of their bodies underdeveloped- does not weaken the conclusion , move on ..
b ) Well developed forelimbs would not have been more advantageous to ancient marsupial lions than well developed hind limbs would have been ]-does not weaken the conclusion 
c)  If the newborn marsupial lion did climb into its mother’s pouch, then paleontologists would be able to find evidence of this fact - out of scope again
d)  Newborn marsupial lions that crawled into their mothers’ pouches could have done so had they not had only their forelimbs developed at birth-this is a bit complicated to comprehend so simplify  - so this says that M-lions have only their forelimbs developed at birth and they could have only climbed into their mother's pouch if they had more than their forelimbs developed , so basically they say that M-lions cannot climb into their mother;s pouch 
e) Newborn marsupial lions would have had only their forelimbs developed if this development were of no use to the marsupial lions -simplify-if this developed is of no use then they don't have to climb into their mother's pouch , since this developement is useless it serves no purpose , so this contradicts the argument and i think this should be the ans.

bb · Answer

Assumptions are my favorite questions

For CR's I usually like to answer the question in my own words. This was not an easy one and I had to read it 3 times to actually get what the point was. My own answer was something along the lines of: The forelimbs are only needed to climb into a pouch Of course this was not an option for the answer choices (ugh). I see some sense in D but it is convoluted and E does look better. The recent discovery that ancient marsupial lions were also born with only their forelimbs developed supports The answer I came up on my own is that

checkoutjay · Answer

IMO E

tough choice between D and E.

DipanjanMitra · Answer

The answer is  .

The reason :-

Joey, born after a short gestation period, has an absolute necessity to go into mother's pouch for further development. Now, to go into the mother's pouch joey needs to climb and for that well developed fore limbs are necessary.

So it can be inferred that well developed fore limbs have their own use for a premature newborn joey.

From the above it can also be inferred that there must be some cause behind every effect. Same is true for the newborn marcupial lions. They also must have some kind of necessity for which the well developed fore limbs were required for them. One of the possibility could be they also needed to climb into their mother's pouches.

ChrisBKnewton · Answer

Hey all,

Great work so far! I'll leave the OA hidden so more people can try it out. When you're ready to see how you did, you can check out this explanation from our GMAT teacher Rich:

https://www.youtube.com/watch?v=pblnPFlvaPI

Enjoy! Let us know if you have any more questions...

Chris

varun2410 · Answer

IMO: ans is E

if there is no use of forlimbs then M linos whould not develope their limbs.

Knewton Verbal Challenge Question: Critical Reasoning

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