首页
登录
职称英语
As the earth’ s surfaces warm, evaporation(蒸发)is drying out forests and soil
As the earth’ s surfaces warm, evaporation(蒸发)is drying out forests and soil
游客
2024-02-06
9
管理
问题
As the earth’ s surfaces warm, evaporation(蒸发)is drying out forests and soils, increasing susceptibility to fire. Last summer, more than 7.3 million acres of U.S. forests burned during an intense drought. Most alarmingly, as an intergovernmental panel concluded in 2001, earth’ s biological systems are already responding to climate change. The current epidemic(传染病)of bark beetles adds a new dimension to the risk of fires.
Mountain bark beetles attack lodgepole, ponderosa(黄松), Douglass fir(枞木), sugar and western white pines, destroying them by injecting a fungus(真菌). The galleries of eggs they lay inside the bark pave the way for the trees’ death within a year. Healthy trees secrete pitch to drown the invaders and plug the holes they bore, but drought dries out the pitch. Woodpeckers and nuthatches keep adult numbers in check, but with warmer winters, beetle populations can quadruple in a year, outpacing their pursuers.
Warming is increasing the reproduction, abundance and geographic range of beetles, destabilizing the age-old, hard won truce between insects and vegetation. Since 1994, mild winters in Wyoming have helped the beetle larvae(幼虫)survive the season. Usually, 80 percent die, but the mortality rate has dropped to less than 10 percent. In Alaska, spruce bark beetles are sneaking in an extra generation a year due to warming, and have destroyed 4 million acres in the Kenai Peninsula in the past five years. "This is another example of global climate change that has deadly implications for my state," declared Alaska’s Republican Sen. Ted Stevens last year.
Warming is also expanding the beetles’ range into higher altitudes. In the past four or five years, they have begun to attack whitebark pines at an elevation of 8,000 feet or higher. Jesse Logan, who works for the Utah Forest Service, told the Billings(Mont.)Gazette last month that this development coincides with an overall wanning trend that began in the 1980s. "Beetles are cold-blooded, so their metabolism is related to the environment they’re in," according to Logan, who said the beetles seem to be a reliable indicator of global climate change. [br] Why do we have more wildfires now than before?
选项
A、Because the number of the bark beetles is decreasing.
B、Because trees where bark beetles live dry out easily and catch fire.
C、Because bark beetles prevent the earth from getting warmer.
D、Because bark beetles are cold-blooded and need fire to warm up their bodies.
答案
B
解析
推断题。根据文章的第一段,气候变暖导致树木及土壤水分量减少,导致火灾数量的增多。由此可见问题在于水分的减少。而这种害虫导致树木死亡,死亡的树木含水量很低,就更容易着火,故选B。
转载请注明原文地址:https://tihaiku.com/zcyy/3427896.html
相关试题推荐
[originaltext]Mostrainforestslieclosetotheequator,wheretheclimate
[originaltext]Mostrainforestslieclosetotheequator,wheretheclimate
Astheearth’ssurfaceswarm,evaporation(蒸发)isdryingoutforestsandsoil
Astheearth’ssurfaceswarm,evaporation(蒸发)isdryingoutforestsandsoil
Astheearth’ssurfaceswarm,evaporation(蒸发)isdryingoutforestsandsoil
Astheearth’ssurfaceswarm,evaporation(蒸发)isdryingoutforestsandsoil
Astheearth’ssurfaceswarm,evaporation(蒸发)isdryingoutforestsandsoil
Astheearth’ssurfaceswarm,evaporation(蒸发)isdryingoutforestsandsoil
Astheearth’ssurfaceswarm,evaporation(蒸发)isdryingoutforestsandsoil
Astheearth’ssurfaceswarm,evaporation(蒸发)isdryingoutforestsandsoil
随机试题
Startingaconversationisaseasyforsomepeopleaseatingandbreathing.H
A—groceryJ—furnitureshopB—roastmeatshopK—electricalapplianceshopC—
[originaltext]W:Soyouareuptosometennisthisafternoonorwhat?M:Well,
下列对期权交易描述正确的是()。A、合约双方都被赋予相应权利B、交易双方承担风险都是无限的C、进行套期保值将不利风险转出D、合约不一定标准化A
发明专利申请人要求适用外国优先权的,必须()。A.申请发明专利的是同一主题
舞蹈《海棠依旧》是下面哪一项芭蕾()A.当代芭蕾 B.现代芭蕾 C.古代芭
钢材合理的屈强比数值应控制在什么范围内?A.0.3~0.45 B.0.4~
浴室、厕所要求地面()。A.耐潮湿 B.有弹性 C.不漏水 D.耐火
柏曼(L.Berman)划分儿童年龄阶段的标准是A.生理发育 B.智力发展
下列同语中加点字的读音完全相同的一组是()。A. B. C. D.
最新回复
(
0
)