PRAXIS2 Latest Exam Braindumps
Question 9: The fossil remain of the first flying vertebrates, the pterosaurs, have intrigued paleontologistsfor more
than two centuries. How such large creatures, which weighed in some cases as much as a piloted
hangglider and had wingspans from 8 to 12 meters, solved the problems of powered flight, and
exactly
what these creatures were-reptiles or birds-are among the questions scientist have puzzled over.
Perhaps the least controversial assertion about the pterosaurs is that they were reptiles. Their skulls,
pelvises, and hind feet are reptilian. The anatomy of their wings suggests that they did not evolve
into the
class of birds. In pterosaurs a greatly elongated fourth finger of each forelimb supported a wing like
membrane. The other fingers were short and reptilian, with sharp claws, in birds the second finger is
the
principle strut of the wing, which consists primarily of features. If the pterosaur walked or remained
stationary, the fourth finger, and with it the wing, could only turn upward in an extended inverted V-
shape
along side of the animal's body.
The pterosaurs resembled both birds and bats in their overall structure and proportions. This is not
surprising because the design of any flying vertebrate is subject to aerodynamic constraints. Both the
pterosaurs and the birds have hollow bones, a feature that represents a saving in weight. In the birds,
however, these bones are reinforced more massively by internal struts.
Although scales typically cover reptiles, the pterosaurs probably had hairy coats. T.H. Huxley
reasoned
that flying vertebrates must have been warm blooded because flying implies a high internal
temperature.
Huxley speculated that a coat of hair would insulate against loss of body heat and might streamline
the
body to reduce drag in flight. The recent discovery of a pterosaur specimen covered in long, dense,
and
relatively thick hairlike fossil material was the first clear evidenced that his reasoning was correct.
Efforts
to explain how the pterosaurs became air-borne have led to suggestions that they launched
themselves
by jumping from cliffs, by dropping from trees, or even by rising into light winds from the crests of
waves.
Each hypothesis has its difficulties. The first wrongly assumes that the pterosaur's hind feet
resembled a
bat's and could served as hooks by which the animal could bang in preparation for flight. The second
hypothesis seems unlikely because large pterosaurs could not have landed in trees without damaging
their wings. The birds call for high waves to channels updrafts. The wind that made such waves
however,
might have been too strong for the pterosaurs to control their flight once airborne.
According to the passage, the lack of critical attention paid to Jane Austen can be explained by all of
the
following nineteenth-century attitudes towards the novel EXCEPT the
A. assurance felt by many people that novels weakened the mind
B. certainly shared by many political commentators that the range of novels was too narrow
C. Lack of interest shown by some critics in novels that were published anonymously
D. fear exhibited by some religious and political groups that novels had the power to portray immoral
characters attractively
E. belief held by some religious and political groups that novels had no practical value.
Correct Answer: B
