Marsupial Lions

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Marsupial Lions

by hk » Fri May 08, 2009 7:19 am
Another one...

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?



A) All animals that are born after a short gestation period are born with some parts of their bodies underdeveloped.

B) Well developed forelimbs would have been more advantageous to ancient marsupial lions than well developed hind limbs would have been.

C) If the newborn marsupial lion did not climb into its mother's pouch, then paleontologists would be able to find evidence that it did so.

D) Newborn marsupial lions that crawled into their mothers' pouches could not have done so had they not had only their forelimbs developed at birth.

E) Newborn marsupial lions would not have had only their forelegs developed if this development were of no use to the marsupial lions.
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by poonam1279 » Fri May 08, 2009 7:38 am
D) Newborn marsupial lions that crawled into their mothers' pouches could not have done so had they not had only their forelimbs developed at birth.
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by scoobydooby » Fri May 08, 2009 8:27 am
would go for E
developed forelimbs help marsupial lions climbs into pouches

A. out of scope

B. out of scope

C. out of scope

D. we do not know if "having only forelimbs" is neccessary for climbing into pouches.

E. correct IMO, says only function of the forelimbs in newborn marsupial lions is to climb in pouches. negate- if newborn lions had developed forelimbs which were useless (which did not help them in climbing into pouches)-argument falls apart

theres a similar question in OG-11 about bats and blood vessels in their wings
Last edited by scoobydooby on Fri May 08, 2009 10:59 pm, edited 2 times in total.

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by kanha81 » Fri May 08, 2009 8:59 am
IMO [spoiler][D][/spoiler]. It directly strenghtens the hypothesis, so there is no point in negating and redirecting against the conclusion to weaken. [spoiler][D][/spoiler] fills in the blank.

what is OA?
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by ManSab » Fri May 08, 2009 9:37 am
..its forelimbs are well developed, so that it can can climb from the cloaca into its mother's pouch for further development

my pick D! --> strengthens the above premise.

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by rs2010 » Fri May 08, 2009 10:07 am
One more for D.

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Re: Marsupial Lions

by 2010gmat » Fri May 08, 2009 10:48 am
hk wrote:Another one...

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?

IMO C, :shock:



A) All animals that are born after a short gestation period are born with some parts of their bodies underdeveloped.

B) Well developed forelimbs would have been more advantageous to ancient marsupial lions than well developed hind limbs would have been.

C) If the newborn marsupial lion did not climb into its mother's pouch, then paleontologists would be able to find evidence that it did so.

D) Newborn marsupial lions that crawled into their mothers' pouches could not have done so had they not had only their forelimbs developed at birth.

E) Newborn marsupial lions would not have had only their forelegs developed if this development were of no use to the marsupial lions.

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by mehravikas » Fri May 08, 2009 4:26 pm
Argument talks about climb and option D talks about crawled....

IMO - C

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by preetosh » Sat May 09, 2009 3:36 am
i too opt for D.
What is OA ?

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by Steppanyaki » Sat May 09, 2009 4:30 am
I agree with Scoobydooby - E.

The question structure and logic is so similar to the question in OG11 about bats and blood vessels.

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by bmlaud » Sun May 10, 2009 3:47 am
IMO D

The argument assumes that there is no other way to climb the pouches.

Option E is misleading - it is analogous to say Marsupial lions had tails, whiskers or nails because lions needed those for their development. It may not be true though.
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by sanp_l » Sun May 10, 2009 5:26 am
One more D.

How do i know if i am correct ? The thread starter might have the right answer i guess.
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by Steppanyaki » Sun May 10, 2009 7:55 am
Ok, I reread the OG question about bats. The focus seems to be different even though the structure is incredibly similar.

But D does seem to make more sense here.

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by agoyal2 » Sun May 10, 2009 9:19 am
IMO E, Whats the OA?

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by thetrystero » Sun May 10, 2009 10:21 pm
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?



A) All animals that are born after a short gestation period are born with some parts of their bodies underdeveloped.

B) Well developed forelimbs would have been more advantageous to ancient marsupial lions than well developed hind limbs would have been.

C) If the newborn marsupial lion did not climb into its mother's pouch, then paleontologists would be able to find evidence that it did so.

D) Newborn marsupial lions that crawled into their mothers' pouches could not have done so had they not had only their forelimbs developed at birth.

E) Newborn marsupial lions would not have had only their forelegs developed if this development were of no use to the marsupial lions.
Situation:
1. joeys are born with well developed forelegs, under developed hind legs.
2. this allows it climb into pouch.
3. baby marsupials also have similarly relative development levels in fore vs hind legs.
4. therefore, they must have needed to climb in to pouch too.

A,B,C: not relevant to argument
D. this is saying that if they had a full range of motion, it would have been harder for them move than if they were crippled in the hind legs.
E. the similar leg development could well have been of no evolutionary purpose to the marsupials even though they served a purpose for the joey.

My answer: E