首页
登录
职称英语
Lichens, probably the hardiest of all plants, live where virtually nothing e
Lichens, probably the hardiest of all plants, live where virtually nothing e
游客
2025-01-13
9
管理
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 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 are believed to supply water, minerals, and physical support to 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 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.
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 to 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. [br] The author mentions "the green film of plant life that grows on stagnant pools" in paragraph 2 in order to explain______.
选项
A、how the sun affects lichens
B、why plants depend on water
C、where fungi become algae
D、what algae are
答案
D
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3910294.html
相关试题推荐
Parentingwasneverapieceofcakeinanyage,butprobablythegreatestso
Parentingwasneverapieceofcakeinanyage,butprobablythegreatestso
[originaltext]You’veprobablyheardtheslogan"savethewhales".Doyoukn
[originaltext]Peoplearenoworderingandpurchasingvirtuallyanythingoverth
[originaltext]Peoplearenoworderingandpurchasingvirtuallyanythingoverth
[originaltext]You’veprobablyheardtheslogan"savethewhales".Doyoukno
[originaltext]You’veprobablyheardtheslogan"savethewhales".Doyoukno
[originaltext]You’veprobablyheardtheslogan"savethewhales".Doyoukno
"Water,whichisessentialforlife,costsnothing.Ontheotherhand,diamon
"Water,whichisessentialforlife,costsnothing.Ontheotherhand,diamon
随机试题
Specialsoftwarehasbeenusedtoenablepassengerstocallfortaxiatalowpr
KarlWilhelmRontgen【B1】______peoplewiththefirstx-raysin1895;thiswas
OntheInternet,adsarearealproblem.They’reaproblemforus,thepeople
UniversitiesBranchOutA)Asneverbeforeintheirlong
竣工决算审计是对项目竣工决算的()进行评价。A.真实性 B.时效性 C
脚手架底部的构造要求是()。A.每根立杆底端应设底座或垫板,且应设纵向、横向扫
促使卵泡生长发育成熟的是A.绒毛膜促性腺激素(hCG) B.绝经期促性腺激素(
有关传染病流行的三个基本环节,错误的是A.传染源、传播途径和易感人群是传染病流行
下列关于弹性的表达中,正确的有( )。Ⅰ需求价格弹性是需求量变动对
以下正确的是()。A刚体惯性力系主矢与简化中心有关 B刚体惯性力系主矢与
最新回复
(
0
)