首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
At the base of a mountain in Tanzania’s Gregory Rift, Lake Natron burns bright red, surrounded by the remains of animals that we
At the base of a mountain in Tanzania’s Gregory Rift, Lake Natron burns bright red, surrounded by the remains of animals that we
admin
2021-01-08
46
问题
At the base of a mountain in Tanzania’s Gregory Rift, Lake Natron burns bright red, surrounded by the remains of animals that were unfortunate enough to fall into the salty water. Bats, swallows and more are chemically preserved in the pose in which they perished, sealed in the deposits of sodium carbonate in the water. The lake’s landscape is bizarre and deadly—and made even more so by the fact that it’s the place where nearly 75 percent of the world’s flamingos(火烈鸟)are born.
The water is so corrosive that it can burn the skin and eyes of unadapted animals. Flamingos, however, are the only species that actually makes life in the midst of all that death. Once every three or four years, when conditions are right, the lake is covered with the pink birds as they stop flight to breed. Three-quarters of the world’s flamingos fly over from other salt lakes in the Rift Valley and nest on salt-crystal islands that appear when the water is at a specific level—too high and the birds can’t build their nests, too low and predators can move briskly across the lake bed and attack. When the water hits the right level, the baby birds are kept safe from predators by a corrosive ditch.
"Flamingos have evolved very leathery skin on their legs so they can tolerate the salt water," says David Harper, a professor at the University of Leicester. "Humans cannot, and would die if their legs were exposed for any length of time. " So far this year, water levels have been too high for the flamingos to nest.
Some fish, too, have had limited success vacationing at the lake as less salty lagoons(泻湖)form on the outer edges from hot springs flowing into Lake Natron. Three species of tilapia(罗非鱼)thrive there part-time. " Fish have a refuge in the streams and can expand into the lagoons when the lake is low and the lagoons are separate," Harper said. "All the lagoons join when the lake is high and fish must retreat to their stream refuges or die. " Otherwise, no fish are able to survive in the naturally toxic lake.
This unique ecosystem may soon be under pressure. The Tanzanian government has once again started mining the lake for soda ash, used for making chemicals, glass and detergents. Although the planned operation will be located more than 40 miles away,drawing the soda ash in through pipelines, conservationists worry it could still upset the natural water cycle and breeding grounds. For now, though, life prevails—even in a lake that kills almost everything it touches.
Why can certain species of tilapia sometimes survive around Lake Natron?
选项
A、They can take refuge in the less salty waters.
B、They can flee quick enough from predators.
C、They can move freely from lagoon to lagoon.
D、They can stand the heat of the spring water.
答案
A
解析
事实细节题。第四段第一句提到,也有些鱼,能偶尔成功地在纳特龙湖待上一段时间,因为咸度较低的泻湖是在流入纳特龙湖的温泉外缘形成的。紧接着第二句具体指出三种罗非鱼会有部分时间在那里成长。由此可知,这三种罗非鱼有时能生存在纳特龙湖周围,是因为泻湖的咸度较低,故答案为A)。
转载请注明原文地址:https://jikaoti.com/ti/oUBFFFFM
0
大学英语六级
相关试题推荐
A、Thecostofmakingpaper.B、Largemachinesandpaper-making.C、Thedevelopmentofpaper-making.D、Howtomakepaperbyhandto
Naturally,inagroupofanimalsasdiverseasthesnakes,andwithsomanyvariedenemies,therearenumerousdefensivereactio
Naturally,inagroupofanimalsasdiverseasthesnakes,andwithsomanyvariedenemies,therearenumerousdefensivereactio
TheHistoryofChineseAmericans[A]ChinesehavebeenintheUnitedStatesforalmosttwohundredyears.Infact,theChines
It’sagoodideatoapplysunscreenbeforeheadingtothebeachifyoudon’twanttoburn.Butformarineanimalslikewhales,t
Oncetheydecidedtohavechildren,MiShelandCarlMeissnertackledthenextbigissue:Shouldtheytrytohaveagirl?Itwas
Peopletravelinglongdistancesfrequentlyhavetodecidewhethertheywouldprefertogobyland,sea,orair.Hardlycananyon
Peopletravelinglongdistancesfrequentlyhavetodecidewhethertheywouldprefertogobyland,sea,orair.Hardlycananyon
Peopletravelinglongdistancesfrequentlyhavetodecidewhethertheywouldprefertogobyland,sea,orair.Hardlycananyon
Peopletravelinglongdistancesfrequentlyhavetodecidewhethertheywouldprefertogobyland,sea,orair.Hardlycananyon
随机试题
垂体病损所致先天性甲状腺功能减低症佝偻病
甲药品经营企业持有《药品经营许可证》,经营方式为药品批发,批准的经营范围为:麻醉药品、精神药品、医疗用毒性药品、化学原料药及其制剂、抗生素原料药及其制剂、生化药品、生物制品(含疫苗)。乙药品经营企业持有《药品经营许可证》,经营方式为药品零售(连锁),经营类
某地下结构采用钻孔灌注桩作抗浮桩,桩径0.6m,桩长15.0m,承台平面尺寸27.6m×37.2m,纵横向按等间距布桩,边桩中心距承台边缘0.6m,桩数为12×16=192根,土层分布及桩侧土的极限侧摩阻力标准值如图6.4—12所示。粉砂抗拔系数取0.7,
符合负债类账户记账规则的是()。
从职业活动内在的道德准则看,与“勤勉”内涵符合的是()。
请根据《义务教育音乐课程标准(2011年版)》基本理念,按照下列要求进行教学设计。教学对象:八年级学生教学内容:欣赏《川江船夫号子》《山丹丹开花红艳艳》要求:(1)设定教学目标与重点。(2)针对教学重点,设计具体的教学策略与过程,其中至少包括2个
学校对违反校规校纪的学生宜实施的惩罚类型是()。
当前我国的改革正在向纵深发展。改革的性质是()。
建立一个视图salary,该视图包括了系号和(该系的)平均工资两个字段,正确的SQL语句是()。
Competitiononthejobmarketisbecomingfierceallthetime.Withfindingajobsodifficult,somestudentschoosetopursuet
最新回复
(
0
)