Grassland songbirds often nest in
the same grassland-wetland complexes
as waterfowl, particularly in a certain
part of those complexes, namely,
(5) upland habitats surrounding wetlands.
Although some wildlife management
procedures directed at waterfowl, such
as habitat enhancement or restoration,
may also benefit songbirds , the impact
(10) of others, especially the control of
waterfowl predators, remains difficult to
predict. For example, most predators
of waterfowl nests prey opportunistically
on songbird nests, and removing
(15) these predators could directly increase
songbird nesting success. Alternatively,
small mammals such as mice
and ground squirrels are important
in the diet of many waterfowl-nest
(20) predators and can themselves be
important predators of songbird
nets. Thus. Removing waterfowl-nest
predators could affect songbird nesting
success through subsequent increases
(25) in small-mammal populations.
In 1995 and 1996, researchers
trapped and removed certain waterfowlnest
predators. primary raccoons and
striped skunks, then observed subse-
(30) quent survival rates for songbird nests.
Surprisingly. They observed no significant
effect on songbird nesting
success. This may be due to several
factors. Neither raccoons nor striped
(35) skunks consume ground squirrels,
which are important predators of songbird
nests. Thus, their removal may
not have led to significant increases
in populations of smaller predators.
(40) Additionally, both raccoons and striped
skunks prefer wetlands and spend little
time in upland habitats; removing these
species may not have increased the
nesting success of songbirds in the
uplands enough to allow detection.

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Q 13:According to the passage, which of the
following is true about the role played
by ground squirrels in the ecology of
grassland-wetland complexes?
A. While not important in the diet of
raccoons or striped skunks, ground
squirrels are a significant source
of food for other waterfowl-nest
predators. for this please refer to the boldfaced statements in line 17 and 34
B. Whereas ground squirrels are
typically important as predators of
songbird nests, their opportunistic
predation on waterfowl nests also
has an observable effect on waterfowl
nesting success.
C. Although most waterfowl-nest
predators prey on small mammals
such as mice and ground squirrels,
populations of ground squirrels tend
to increase quickly enough to compensate
for this level of predation.
D. Although ground squirrels have been
known to prey on songbird nests, a
larger portion of their diets is usually
provided by predation on waterfowl
nests.
E. Since larger predators tend to prefer
small mammals to songbird eggs as
a food source, a large population of
ground squirrels plays an important
role in controlling opportunistic
predation on songbird nests.
Answer:
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Q 15:
The primary purpose of the passage is to
A. describe some procedures used for
wildlife management and consider
some problems associated with the
execution of those procedures
B. outline a problem related to a wildlife
management procedure and offer
potential explanations for the results of
an experiment bearing on that problem problem is outlined in boldfaced lines 6-11 and after line 31 the entire passage talks about the result and its explanation.
C. present experimental results that
illustrate the need for certain wildlife
management procedures and point out
some inconsistencies in those results
D. argue that a certain procedure used
for wildlife management should be
modified because of its unintended
consequences
E. propose that further experiments be
performed to assess the long-term
effects of certain wildlife management procedures

I am not sure whether the OA's are correct or not. I am posting this question just to verify the OA's and to know my mistake

OA=> 13A, 15B
IMO=>13E, 15 C