Bavarian quarry workers_LSAT

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Bavarian quarry workers_LSAT

by gmat_perfect » Mon Jun 14, 2010 11:08 am
In 1860 Bavarian quarry workers discovered the impression of a feather in a limestone slab dating to the Mesozoic era. It had previously been assumed that birds developed only after the close of the Mesozoic era and after the disappearance of pterosaurs, a species characteristic of that era. But there in limestone lay the imprint of a fully aerodynamic, three-inch-long feather. This, therefore, must have been the earliest bird-certainly the earliest found to the date.

The argument assumes which one of the following?

(A) The creature to which the feather belonged was a descendant of the pterosaurs.
(B) Birds with such feathers were preceded by species of birds with less-developed feathers.
(C) In the Mesozoic era, no creatures other than birds had such feathers.
(D) The feather belonged to a Mesozoic creature that was neither a pterosaur nor a bird, but intermediate between them.
(E) The earliest bird flew in an awkward manner.

OA: Later
Source: — Critical Reasoning |

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by sk818020 » Mon Jun 14, 2010 11:47 am
IMO C.

If C is not true, could the author possibly conclude the feather came from a bird?

What is the OA?
Last edited by sk818020 on Mon Jun 14, 2010 3:24 pm, edited 1 time in total.

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by hardik.jadeja » Mon Jun 14, 2010 3:18 pm
One more vote for C.

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by RumpelThickSkin » Mon Jun 14, 2010 3:24 pm
gmat_perfect wrote:In 1860 Bavarian quarry workers discovered the impression of a feather in a limestone slab dating to the Mesozoic era. It had previously been assumed that birds developed only after the close of the Mesozoic era and after the disappearance of pterosaurs, a species characteristic of that era. But there in limestone lay the imprint of a fully aerodynamic, three-inch-long feather. This, therefore, must have been the earliest bird-certainly the earliest found to the date.

The argument assumes which one of the following?

(A) The creature to which the feather belonged was a descendant of the pterosaurs.
(B) Birds with such feathers were preceded by species of birds with less-developed feathers.
(C) In the Mesozoic era, no creatures other than birds had such feathers.
(D) The feather belonged to a Mesozoic creature that was neither a pterosaur nor a bird, but intermediate between them.
(E) The earliest bird flew in an awkward manner.

OA: Later
IMO C - other options do not make any reference to the conclusion.

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by RumpelThickSkin » Mon Jun 14, 2010 3:24 pm
gmat_perfect wrote:In 1860 Bavarian quarry workers discovered the impression of a feather in a limestone slab dating to the Mesozoic era. It had previously been assumed that birds developed only after the close of the Mesozoic era and after the disappearance of pterosaurs, a species characteristic of that era. But there in limestone lay the imprint of a fully aerodynamic, three-inch-long feather. This, therefore, must have been the earliest bird-certainly the earliest found to the date.

The argument assumes which one of the following?

(A) The creature to which the feather belonged was a descendant of the pterosaurs.
(B) Birds with such feathers were preceded by species of birds with less-developed feathers.
(C) In the Mesozoic era, no creatures other than birds had such feathers.
(D) The feather belonged to a Mesozoic creature that was neither a pterosaur nor a bird, but intermediate between them.
(E) The earliest bird flew in an awkward manner.

OA: Later
IMO C - other options do not make any reference to the conclusion.

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by diebeatsthegmat » Tue Jun 15, 2010 5:08 pm
gmat_perfect wrote:In 1860 Bavarian quarry workers discovered the impression of a feather in a limestone slab dating to the Mesozoic era. It had previously been assumed that birds developed only after the close of the Mesozoic era and after the disappearance of pterosaurs, a species characteristic of that era. But there in limestone lay the imprint of a fully aerodynamic, three-inch-long feather. This, therefore, must have been the earliest bird-certainly the earliest found to the date.

The argument assumes which one of the following?

(A) The creature to which the feather belonged was a descendant of the pterosaurs.
(B) Birds with such feathers were preceded by species of birds with less-developed feathers.
(C) In the Mesozoic era, no creatures other than birds had such feathers.
(D) The feather belonged to a Mesozoic creature that was neither a pterosaur nor a bird, but intermediate between them.
(E) The earliest bird flew in an awkward manner.

OA: Later
OA is C