The canopy, the upper level of the trees in the rain forest, holds a plethora of climbing mammals of moderately large size, whic

admin2022-12-06  14

问题 The canopy, the upper level of the trees in the rain forest, holds a plethora of climbing mammals of moderately large size, which may include monkeys, cats, civets, and porcupines. Smaller species, including such rodents as mice and small squirrels, are not as prevalent overall in high tropical canopies as they are in most habitats globally.
    Small mammals, being warm-blooded, suffer hardship in the exposed and turbulent environment of the uppermost trees. Because a small body has more surface area per unit of weight than a large one of similar shape, it gains or loses heat more swiftly. Thus, in the trees, where shelter from heat and cold may be scarce and conditions may fluctuate, a small mammal may have trouble maintaining its body temperature.
    Small size makes it easy to scramble among twigs and branches in the canopy for insects, flowers, or fruit, but small mammals are surpassed, in the competition for food, by large ones that have their own tactics for browsing among food-rich twigs. The weight of a gibbon (a small ape) hanging below a branch arches the terminal leaves down so that fruit-bearing foliage drops toward the gibbon’s face. Walking or leaping species of a similar or even larger size access the outer twigs either by snapping off and retrieving the whole branch or by clutching stiff branches with the feet or tail and plucking food with their hands.
    Small climbing animals may reach twigs readily, but it is harder for them than for large climbing animals to cross the wide gaps from on tree crown to the next that typify the high canopy. A macaque or gibbon can hurl itself farther than a mouse can: it can achieve a running start, and it can more effectively use a branch as a springboard, even bouncing on a climb several times before jumping. The forward movement of a small animal is seriously reduced by the air friction against
    the relatively large surface area of its body. Finally, for the many small mammals that supplement their insect diet with fruits or seeds, an inability to span open gaps between tree crowns may be problematic, since trees that yield these foods can be sparse.
Large mammals have all of the following advantages over smaller ones in the canopy EXCEPT that________.

选项 A、it’s easier for them to stay warm
B、they outsmart small mammals in the search for food
C、their food sources are easier to find
D、they are physically stronger and more agile

答案D

解析 细节题。根据第二段中的“Because a small body…it gains or loses heat more swiftly”可排除A。根据第三段中的“…but small mammals are surpassed,in the competition for food,by large ones that have their own tactics for browsing among food-rich twigs”可排除B。根据最后一段中的“…an inability to span open gaps between tree crowns may be problematic,since trees that yield these foods can be sparse”可排除C。根据最后一段第一句“Small climbing animals may reach twigs readily”可知小的攀爬动物相对大的动物,更容易到达树梢,因此更敏捷。所以D项中的“more agile”不正确。故本题选D。
转载请注明原文地址:https://kaotiyun.com/show/sOjD777K
0

相关试题推荐
最新回复(0)