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
2023-12-22
26
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] Which of the following questions does the passage answer?
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 be?
D、Where do lichens usually occur?
答案
D
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3295732.html
相关试题推荐
[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
"Water,whichisessentialforlife,costsnothing.Ontheotherhand,diamon
Howwelookandhowweappeartoothersprobablyworriesusmorewhenarein
Howwelookandhowweappeartoothersprobablyworriesusmorewhenarein
Howwelookandhowweappeartoothersprobablyworriesusmorewhenarein
随机试题
PassageOne(1)Someoneelsehadsaidthat-."Likemustmarrylikeor
A—collectiveactionI—psychologicalsupportB—competitoranalysisJ—performance-
[originaltext]Thebankingprofessiondoesn’thaveaverygoodreputationfo
一个加密系统数学符号描述如下:M是明文,C是密文,K是密钥,E是加密算法,D是解
关于艺人(演员)演艺经纪合同的特色条款说法正确的是()。A.合同期限过长
狂犬病毒可以感染温血动物,但造成人类感染的主要传染源是下列哪一种()A.带病毒
肝硬化时腹水形成的原因是( )。A.门静脉压力升高 B.血浆胶体渗透压降低
某男,45岁。平素喜饮浓荼,嗜好烟酒,经常熬夜。现入睡困难,且多梦易醒,心悸健忘
为了促进出口,政府一般采取的干顶措施是()A.技术标准和卫生检疫标准 B.歧
16岁男患,洗浴时无意中触及右膝下内侧硬性突起,无疼痛,膝关节运动正常。最可能的
最新回复
(
0
)