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
Lichens. probably the hardiest of all plants, live where virtually nothing else can---not just on rugged mountain peaks but
Lichens. probably the hardiest of all plants, live where virtually nothing else can---not just on rugged mountain peaks but
admin
2005-01-30
104
问题
Lichens. probably the hardiest of all plants, live where virtually nothing else can---not
just on rugged mountain peaks but also on sunbaked desert rocks. They are usually the
first life to appear on a mountainside that has been scraped bare by an avalanche.
Unlike other members of the plant kingdom, lichens are actually a partnership between
5 two plants. The framework of a lichen is usually a network of minute hairlike fungus that
anchors the plant, The other component is an alga (similar to the green film of plant life
that grows on stagnant pools) that is distributed throughout the fungus. Being green plants,
algae are capable of photosynthesis--that is, using energy from the Sun to manufacture
their own food. The fungi arc believed to supply water, minerals, and physical support to
10 the partnership.
Lichens are famous for their ability to survive ~ water shortage. When water is scarce
(as is often the case on a mountain), lichens may become dormant and remain in that
condition for prolonged periods of time. Some lichens can even grow where there is no
rain at all, surviving on only occasional dew--the moisture that condenses on the surface
15 of the plants at night, And unlike most other plants, lichens are little affected by the strong
ultraviolet rays in the mountains.
Lichens use little energy, for they grow slowly. Some grow so slowly and are so old
that they are called "time stains." You may find lichens that are centuries old; certain of
these lichen colonies have been established for an estimated 2,000 years.
20 For decades, scientists wondered how the offspring of an alga and a fungus got together
to form a new lichen, it seemed unlikely that they would just happen lo encounter one
another. It was finally discovered that in many cases the two partners have never been
separated. Stalklike "buds" that form on certain lichens are broken off by the wind or by
animals; these toll or are blown to a new location
选项
A、Where can the oldest lichens be found?
B、How long does it take for lichens to establish themselves?
C、How large can lichens he?
D、Where do lichens usually occur?
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/z6yO777K
0
托福(TOEFL)
相关试题推荐
WilliamGilbertandMagnetismA16thand17thcenturiessawtwogreatpioneersofmodernscience:GalileoandGilbert.Theimpac
CompletethesentencesbelowusingNOMORETHANTWOWORDS/ORANUMBERfromthepassage.Writeyouranswersinboxes21-24onyo
ClassifythefollowingcharacteristicsasrelatingtoASocialScienceBMedicalScienceCBothSocialScienceandMedicalScien
ThewaythebrainbuysSupermarketstakegreatcareoverthewaythegoodstheysellarearranged.Thisisbecausetheyknowal
TheStudyofChimpanzeeCultureA.Afterstudyingthesimilaritiesbetweenchimpanzeesandhumansforyears,researchershav
Completethenotesbelow.UseNOMORETHANTHREEWORDSORANUMBERforeachanswer.INTERNATIONALDRIVINGLICENSESFACTS
SeverallargeearthquakesweretriggeredbytheeruptionofPinatuboon15thJune1991becauseofthe(36)ofthesummit.The
Choosethecorrectanswer,A,BorC.Crocodilesindryareasliveincaveslocated
(Differentfourteen)cropswere(beinggrown)8,600years(ago)bysomeoftheworld’searliest(farmers).
A、SheledhertribetovictoryagainstthecolonistsB、Shewasconsideredtobeextremelybeautiful.C、ShecreatedpopularAmeri
随机试题
Forthispart,youareallowed30minutestowriteacompositiononthetopic"ALetterofComplaint".Youshouldwriteatleast
患者,女,39岁。因上呼吸道感染使用青霉素治疗,在用药后10天,出现发热、皮肤瘙痒、关节肿胀、淋巴结肿大、腹痛等现象,根据症状患者最可能出现的是
茵陈蒿汤的组成药物是()
用酸度计测定溶液的酸度,若溶液的pH值为4左右,对酸度计进行校正时需选用的标准缓冲液是
背景材料:某二级公路的主要工序如下表:施工单位编制了如下图所示的网络计划。施工中发生了如下事件:事件1:由于施工单位设备故障,导致C工作中断4d。事件2:由于百年一遇的冰雪灾害,导致D工作晚开工15d。事件3:由于图纸晚到,导致E工作停工1
课税对象、征收比例或数额等制定公布后,在执行过程中单位和个人可根据实际情况对征税标准进行适当变更或修改。()
左边给定的是纸盒的外表面,右边哪一项不能由它折叠而成?()
下列针对总体审计方案的说法,错误的是()。
居民甲在某商场购得1台“多功能食品加工机”,回家试用后发现该产品只有一种功能,遂向商场提出退货,商场答复:“该产品说明书未就其使用性能作明确说明,且产品本身无质量问题,所以顾客应向厂家索赔,商场概不负责。”对此,顾客应该怎么办?()
设a一b=一2,则a3一+6ab一b3=().
最新回复
(
0
)