首页
登录
职称英语
The forest from which Man takes his timber is the tallest and most impressiv
The forest from which Man takes his timber is the tallest and most impressiv
游客
2024-06-11
2
管理
问题
The forest from which Man takes his timber is the tallest and most impressive plant community on Earth. In terms of Man’s brief life it appears permanent and unchanging, save for the seasonal growth and fall of the leaves, but to forester it represents the climax of a long succession of events.
No wooded landscape we see today has been forest for all time. Plants have minimum requirements of temperature and moisture and, in ages past, virtually every part of Earth’s surface has at some time been either too dry or too cold for plants to survive. However, as soon as climatic conditions change in favour of plant life, a fascinating sequence of changes occurs, called a primary succession.
First to colonize the barren land are the lowly lichens, surviving on bare rock. Slowly, the acids preduced by these organisms crack the rock surface, plant debris accumulates, and mosses establish a shallow root-hold. Ferns may follow and, with short grasses and shrubs, gradually form a covering of plant life. Roots probe even deeper into the developing soil and eventually large shrubs give way to the first trees. These grow rapidly, cutting off sunlight from the smaller plants, and soon establish complete domination-closing their ranks and forming a climax community which may endure for thousands of years.
Yet even this community is not everlasting. Fire may destroy it outright and settlers may cut it down to gain land for pasture or cultivation. If the land is then abandoned, a secondary succession will take over, developing nmch faster on the more hospitable soil. Shrubs and trees are among the early invaders, their seeds carried by the wind, by birds and lodged in the coats of mammals.
For as long as it stands and thrives, the forest is a vast machine, storing energy and many elements essential for life. [br] What has sometimes caused plants to die out of the past?
选项
A、Interference from foresters.
B、Variations in climate.
C、The absence of wooded land.
D、The introduction of new type of plants.
答案
B
解析
第二段中,作者提到了气候是植物生长的基本条件,而气候一旦变得恶劣,植物可能会灭绝。
转载请注明原文地址:https://tihaiku.com/zcyy/3629550.html
相关试题推荐
AreconstructionofanancienttreefromoneofEarth’sfirstforestsreveal
[originaltext]Mostforestfiresarecausedbyhumancarelessness,negligenc
InMedievalEnglandthetallesthorseswereriddenbypeopleofthehighest
InMedievalEnglandthetallesthorseswereriddenbypeopleofthehighest
InMedievalEnglandthetallesthorseswereriddenbypeopleofthehighest
InMedievalEnglandthetallesthorseswereriddenbypeopleofthehighest
InMedievalEnglandthetallesthorseswereriddenbypeopleofthehighest
InMedievalEnglandthetallesthorseswereriddenbypeopleofthehighest
RainforestsTropicalrainforest
MuchofCanada’sforestryproductiongoestowardsmakingpulpandpaper.Acc
随机试题
Itwouldbeinterestingtodiscoverhowmanyyoungpeoplegotouniversityw
[audioFiles]audio_eham_j69_001(20082)[/audioFiles]A、French.B、American.C、Spani
按照教育部2005年《普通高等学校学生管理规定》,对完成本专业学业同时辅修其他专
《普通高中地理课程标准(实验)》中对情感态度与价值观形成的评价,提出“对地理学科
发热伴寒战常见于A.白血病 B.传染性单核细胞增多症 C.急性胆囊炎
谭某拥有一套建筑面积为140m2的住宅,位于一幢钢筋混凝土结构高层住宅楼的12层
28岁孕妇,妊娠35周,胎膜早破12小时收入院。产科检查:LOT胎头。胎心率14
以画虾著称的画家是( )。A.齐白石 B.徐悲鸿 C.吴冠中
民事合同可以分为诺成合同与实践合同。下列合同中,属于实践合同的是( )。A.买
根据《建筑工程施工质量验收统一标准》,单位工程质量验收合格的规定有( )。A.所
最新回复
(
0
)