首页
登录
职称英语
Coral reefs are one of the most fragile, biologicallycomplex, and diverse marin
Coral reefs are one of the most fragile, biologicallycomplex, and diverse marin
游客
2024-01-13
17
管理
问题
Coral reefs are one of the most fragile, biologically
complex, and diverse marine ecosystem on Earth. This
ecosystem is one of the fascinating paradoxes of the bio-
sphere: how do clear, and thus nutrient-poor, waters sup-
(5) port such prolific and productive communities? Part of the
answer lies within the tissues of the corals themselves.
Symbiotic cells of algae known as zooxanthellae carry out
photosynthesis using the metabolic wastes of the coral
thereby producing food for themselves, for their corals,
(10) hosts, and even for other members of the reef community.
This symbiotic process allows organisms in the reef com-
munity to use sparse nutrient resources efficiently.
Unfortunately for coral reefs, however, a variety of
human activities are causing worldwide degradation of
(15) shallow marine habitats by adding nutrients to the (water.
Agriculture, slash-and-burn land clearing, sewage disposal
and manufacturing that creates waste by-products all
increase nutrient loads in these waters. Typical symptoms
of reef decline are destabilized herbivore populations and
(20)an increasing abundance of algae and filter-feeding
animals.
Declines in reef communities are consistent with observa-
tions that nutrient input is increasing in direct proportion to
growing human populations, thereby threatening reef com-
(25) munities sensitive to subtle changes in nutrient input to
their waters.
选项
A、describing the effects of human activities on algae in coral reefs
B、explaining how human activities are posing a threat to coral reef communities
C、discussing the process by which coral reefs deteriorate in nutrient-poor waters
D、explaining how coral reefs produce food for themselves
E、describing the abundance of algae and filter-feeding animals in coral reef areas
答案
B
解析
This question asks you to identify the primary concerns of the passage. The best answer is B. The first paragraph describes how coral reefs survive in nutrient-poor waters. The second paragraph states that human activities are adding nutrients to shallow marine habitats, thus threatening the survival of coral reef communities. Choices A and E can be eliminated because an increase in algae and filter-feeding animals is mentioned in the context of the passage’s larger concern with the negative effects of human activities on coral reefs. Choice C is incorrect because the first paragraph of the passage explains how coral reefs survive in nutrient-poor waters; the deterioration of coral reef communities has occurred as a result of the increase in nutrients in their habitats. Choice D can be eliminated because the first paragraph states that symbiotic cells of algae known as zooxanethellae produce food for coral reef communities.
转载请注明原文地址:https://tihaiku.com/zcyy/3359866.html
相关试题推荐
Coralreefsareoneofthemostfragile,biologicallycomplex,anddiversemarin
Coralreefsareoneofthemostfragile,biologicallycomplex,anddiversem
Coralreefsareoneofthemostfragile,biologicallycomplex,anddiversem
Coralreefsareoneofthemostfragile,biologicallycomplex,anddiversem
Coralreefsareoneofthemostfragile,biologicallycomplex,anddiversem
Coralreefsareoneofthemostfragile,biologicallycomplex,anddiversem
METAMORPHOSIS:A、diverseactivityB、recurringmovementC、pausefrompressureD、pr
EQUABLE:A、unlimitedB、unbalancedC、fragileD、peripheralE、destructiveB
METAMORPHOSIS:A、diverseactivityB、recurringmovementC、pausefrompressureD、pr
Thewell-trainedengineermustunderstandfieldsasdiverseasphysics,economic
随机试题
大约有四分之一的美国青年人没有阅读能力,这简直令人难以置信。(incredible)ThenumberofyoungpeopleintheUnit
_______you_______anydoubtonthedeliveryreceipt,contactusat40089666.A、
我宁愿同朋友行走在黑暗中,也不愿独自徘徊在光亮处。(wouldrather…than)Iwouldratherwalkwithfriendsin
妊娠合并糖尿病有确诊意义的是A.服50g糖1小时抽静脉血测血糖值≥7.8mmol
关于下斜肌,错误的是A.为所有眼外肌中最短者 B.从起点到止端一直与周围组织关
下列哪些不是引起血管舒张的神经机制()A.副交感舒血管神经兴奋 B.交感舒
前牙反矫治后是否复发,主要与下列哪项有关A.治疗措施是否适当 B.保持时间长短
如图4,该局部的作者是() A.德拉克罗瓦 B.席里科 C.米勒 D.
一般来说,股票的特征包括()。A.返还性 B.流通性 C.收益性 D
企业在职培训的机会成本包括()。A.在职培训支付的场地费 B.邀请外部
最新回复
(
0
)