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
Environmental scientists observe that it is of great significance to protect wildlife and wild places ff human beings want to su
Environmental scientists observe that it is of great significance to protect wildlife and wild places ff human beings want to su
admin
2010-06-18
41
问题
Environmental scientists observe that it is of
great significance to protect wildlife and wild places
ff human beings want to survive. We must under-
stand the important links between ourselves and the
wild plants and animals in our environmental
【1】______ system. 【1】______
Diseases and insects can develop to destroy
some kinds of plants and animals. So a supply of
different kinds of plants is needed. The new species
can be found in the wild or be obtained by Scientists
who mix【2】______material from different species.【2】______
For example, 100 years ago, scientists grew
the European vine on【3】______from the American 【3】______
vine. In this way the European【4】______ 【4】______
industry was saved.
In recent years, scientists have expressed concern
that coffee trees in Brazil and soybean plants in
America come from limited wild species. They are
easily attacked by insects, diseases, or severe
weather conditions.
Scientists are also concerned about the loss of
traditional farm animals. For example, almost 115
out of the original【5】______kinds of cattle in 【5】______
Europe and the Mediterranean area are endangered.
Traditional farm animals can be very valuable,
e.g. a rare European sheep, Cornish hen etc. Some
scientists say this kind of hen can be mated with
other species of chickens to introduce a
【6】______ bird for food. 【6】______
Wild plants and animals are important to medicine,
too. A study shows that about 40 percent of
the medicines in U.S. contain drugs from plants,
animals, etc. For example, cancer scientists are using
a plant to fight a cancer of【7】______ 【7】______
Wild plants and animals are disappearing at an
increasing speed, yet there are still success stories.
For example, the number of elephants killed
【8】______in Africa has decreased dramatically. 【8】______
In another case, 400 gorillas survive in a
【9】______area in Africa because Rwanda developed【9】______
an important business that relies on protecting
the gorillas.
Another successful program takes the endangered
animals from their natural homes to protected
zones where they can【10】______safely. 【10】______
【7】
Environmental scientists say protecting wildlife and wild places is extremely important if the world is to continue to support human life. These experts say we must understand the important links between ourselves and the wild plants and animals in our environmental support system. They note that no one knows for sure which of these plants and animals may be useful to us in the future.
Through the years, diseases and insects develop that can destroy some kinds of plants and animals. Farmers then need a new supply of different kinds of plants to grow and animals to raise for food and work. These new species are found in the wild. Or scientists mix genetic material from many different species to develop new ones. For example, 100 years ago, an insect killed off European grape plants. But scientists discovered that American grape plants were not affected by the insect. So the scientists grew the European wine on roots from the American vine. The grapes produced in this way saved the European wine industry.
In recent years, scientists have expressed concern that almost every coffee tree in Brazil comes from one kind of plant. And all soybean plants in the United States come from six kinds of soybeans found in one place in Asia. The scientists fear that a change in weather conditions or an attack by insects or disease, could destroy Brazil’s coffee trees and America’s soybean plants. This would not happen if we grew different kinds of coffee trees and soybean plants. They would not all be affected by the same weather, insects or disease.
Scientists also are concerned about the loss of many species of traditional farm animals. For example, almost 115 of the original 145 kinds of cattle in Europe and the Mediterranean area are in danger of dying out.
Traditional kinds of farm animals can be very valuable. A rare European sheep, for example, has been used to produce a kind of sheep that can survive where the weather is very hot. And it still produces good wool. Other scientists have worked with the Cornish hen. They say it can be mated with other species of chickens to produce a fast-growing bird for food.
Wild plants and animals also are important to modern medicine. One study say that 40 percent of the medicines used each year in the United States contain drugs that come from plants, animals or small living organisms. For example, cancer scientists are using a periwinkle plant from Madagascar. The plant contains a chemical that may be used to fight leukemia, a cancer of the blood. Other chemicals from plants provide medicines that fight diseases such as malaria. Others improve heart and lung action, or kill pain, or stop dangerous growths. Yet scientists have been able to study only a small number of the world’s plants to find their value as medicines.
While plant and animal species are disappearing at a rapidly increasing rate throughout the world, scientists note some success stories. For example, the number of elephants killed illegally in Africa has fallen sharply. Eighty nine thousand were killed in 1983. Forty six thousand were killed one year later.
Successful efforts also have been made in protecting Africa’s endangered mountain gorillas. Almost 400 of the gorillas survive in a volcano area on the border of Rwanda, Uganda and Zaire. The mountain gorilla population has remained about the same for 15 years. This happened, in part, because Rwanda developed an important business that depends on protecting the gorillas. Visitors there can pay to get close to watch the gorillas in the animals’ traditional home area.
Another successful program takes endangered animals out of their natural homes. The animals are put into zoos or their protected areas where they can reproduce in safety. The goal of many of these programs is to produce enough animals to put back into the wild.
选项
答案
blood
解析
转载请注明原文地址:https://jikaoti.com/ti/OS3YFFFM
0
专业英语八级
相关试题推荐
Howisitthatthelouderthecallsfor"civility,"thelesscivilthebehavior?OnAmericancampusestoday,thecallforcivili
Goodmorning.Thediscussiontopicfortoday’sseminaris"HomelessnessinAmerica."IntheUnitedStates,homelessnesshas【C1】
Goodmorning.Thediscussiontopicfortoday’sseminaris"HomelessnessinAmerica."IntheUnitedStates,homelessnesshas【C1】
ForyearswehavebeentalkingaboutaddictiontotheInternet,andthentothemobilephone.ArecentsurveyinUKfoundthat_
Oneofthemostunexpectedthingsabouthavingchildrenishowthequesttomoldperfectlittlehumansultimatelybecomesaproj
Weuselanguageprimarilyasameansofcommunicationwithotherhumanbeings.Eachofusshareswiththecommunityinwhichwe
TheHeadofSlateofCanadaisrepresentedby______.
Itcanbeinferredthatthedeafboy’slifeintheorphanagewasTheauthorwas______whenhetriedtoprotectthedeafkidag
WhosemasterpieceTheGreatGatsbymadehimoneofthegreatestAmericannovelists?
随机试题
下列日常生活的说法,不正确的是()。
治疗头痛,疗效广泛首选
某施工期单位承接了某山区二级公路4.5km的路基路面施工任务。合同段有一段长450m的两车道隧道和一座长20m的简支梁桥。隧道位于软弱围岩地段,桥梁采用重力式u型桥台,整个合同段均为沥青混凝土路面。在隧道施工方案中有如下要求:(1)在隧
不属于施工质量控制过程的是( )。
关于建设工程索赔成立条件的说法,正确的是()。
有限责任公司和股份有限公司的财务会计报告编制完成后,应当先行委托注册会计师进行审计,并将注册会计师出具的审计报告随同财务会计报告一并对外提供。()
回归系数检验不显著的原因主要有()。Ⅰ.变量之间的多重共线性Ⅱ.变量之间的异方差性Ⅲ.模型变量选择的不当Ⅳ.模型变量选择没有经济意义
2010年5月1日,甲公司以一项专利权和银行存款300万元向乙公司投资(甲公司和乙公司不属于同一控制的两个公司),占乙公司注册资本的70%,该专利权的账面原价为5000万元,已计提累计摊销600万元,已计提无形资产减值准备200万元,公允价值为4000万
AmericanRomanticPeriodisendedwith______LeavesofGrass.
Ifyouareworried_____theproblem,youshoulddosomethingaboutit.
最新回复
(
0
)