The sloth bear, an insect-eating
animal native to
behavior that is truly distinct from that of
Line other bear species: the females carry
(5) their cubs (at least part-time) until the
cubs are about nine months old, even
though the cubs can walk on their own
at six months. Cub-carrying also occurs
among some other myrmecophagous
(10) (ant-eating) mammals; therefore, one
explanation is that cub-carrying is
necessitated by myrmecophagy, since
myrmecophagy entails a low metabolic
rate and high energy expenditure in
(15) walking between food patches. How-
ever, although polar bears’ locomotion
is similarly inefficient, polar bear cubs
walk along with their mother. Further-
more, the daily movements of sloth
(20) bears and American black bears—
which are similar in size to sloth bears
and have similar-sized home ranges—
reveal similar travel rates and distances,
suggesting that if black bear cubs are
(25) able to keep up with their mother, so
too should sloth bear cubs.
An alternative explanation is defense
from predation. Black bear cubs use
trees for defense, whereas brown bears
(30) and polar bears, which regularly inhabit
treeless environments, rely on aggres-
sion to protect their cubs. Like brown
bears and polar bears (and unlike other
myrmecophagous mammals, which are
(35) noted for their passivity), sloth bears
are easily provoked to aggression.
Sloth bears also have relatively large
canine teeth, which appear to be more
functional for fighting than for foraging.
(40) Like brown bears and polar bears,
sloth bears may have evolved in an
environment with few trees. They are
especially attracted to food-rich
grasslands; although few grasslands
(45) persist today on the Indian subcontinent,
this type of habitat was once wide-
spread there. Grasslands support
high densities of tigers, which fight and
sometimes kill sloth bears; sloth bears
(50) also coexist with and have been killed
by tree-climbing leopards, and are often
confronted and chased by rhinoceroses
and elephants, which can topple trees.
Collectively these factors probably
(55) selected against tree-climbing as a
defensive strategy for sloth bear cubs.
Because sloth bears are smaller than
brown and polar bears and are under
greater threat from dangerous animals,
(60) they may have adopted the extra pre-
caution of carrying their cubs. Although
cub-carrying may also be adoptive for
myrmecophagous foraging, the behavior
of sloth bear cubs, which climb on their
(65) mother’s back at the first sign of danger,
suggests that predation was a key
stimulus.
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Answer:
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Q11:
Which of the following, if true, would most weaken the author’s argument in lines 18-26 (“Furthermore … sloth bear cubs”)?
Answer:
这道题目答案应该是C啊,为什么选D呢,D定位不对?大家说说.
C 是SUPPORT 不是WEAKEN。if the home ranges of the black bears are bigger than those of some sloth bears then it means the black bear cubs should move more than the sloth bear cubs do.
D是 WEAKEN : When home ranges and body size are same between sloth bears and black bears, blacks bears have a more efficient lomocation than sloth bears do , so that black bear cubs can move more efficiently than sloth bear cubs, 就是说SLOTH BEAR CUBS的运动不如BLACK BEAR CUBS 的运动有效所以需要妈妈背着
刚才没讲清楚， LINE 18~26行中作者是论述SLOTH BEAR CUB 小熊应该不用妈妈背。文章一开始讲了SLOTH BEAR 妈妈背小熊的现象是与其他熊类不同的 并给出一种解释这种现象发生在食虫类熊中。15行 HOWEVER开始转折，先讲与SLOTH BEAR 的LOMOCATION 相同的北极熊就不用妈妈背，18行FUTHERMORE是递进一直到26行 列举了BLACK BEAR 与SLOTH BEAR许多 的相同处并指出BLACK BEAR CUBS 不用妈妈背，18~26的论点是SLOTH BEAR CUBS也应该不用妈妈背。15行HOWEVER 后反驳了第一种解释所以第二段给出另一个解释并证明新解释是对的
11题是逻辑题，定位的方法是不是多用于细节题呀
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