People are confused in their attempts to control malaria in Europe in the early 1900s, because scientists ______.A．identified only one mosquito species instead of six speciesB．thought only three mosquito species transmitted diseaseC．thought there was only one mosquito speciesD．did not know what species was being studied
People are confused in their attempts to control malaria in Europe in the early 1900s, because scientists ______.
A．identified only one mosquito species instead of six species
B．thought only three mosquito species transmitted disease
C．thought there was only one mosquito species
D．did not know what species was being studied
相关考题：
Quality control charts show a characteristic of the product or service against:A . the specification limitsB . customer requirementsC . control limits based on three standard deviations in each directionD . control limits based on six standard deviations in each directionE . A and D only
129 Quality control charts show a characteristic of the product or service against:A. the specification limits.B. customer requirements.C. control limits based on three standard deviations in each direction.D. control limits based on six standard deviations in each direction.E. A and D only
175 Quality control charts show a characteristic of the product or service against:A. the specification limitsB. customer requirementsC. control limits based on three standard deviations in each directionD. control limits based on six standard deviations in each directionE. A and D only
"Hidden" Species May Be Surprisingly CommonCryptic species animals that appear identical but are genetically quite distant—may be much more widespread than previously thought. The findings could have major implications in areas ranging from biodiversity estimates and wildlife management, to our understanding of infectious diseases and evolution.Reports of cryptic species have increased dramatically over the past two decades with the advent of relatively inexpensive DNA sequencing technology. Markus Pfenninger and Klaus Schwenk, of the Goethe-Universitat, in Frankfurt, Germany, analyzed all known data on cryptic animal species and discovered that they are found in equal proportions throughout all major branches of the animal kingdom and occur in equal numbers in all biogeographieal regions.Scientists had previously speculated that cryptic species were predominantly found in insects and reptiles, and were more likely to occur in tropical rather than temperate regions. "Species that are seemingly widespread and abundant could in reality be many different cryptic species that have low populations and are highly endangered. " Says Pfenninger. Until the genetic information of all species in at least one taxon is thoroughly studied, no one will know just how many cryptic species exist. "It could be as high as 30%. " Pfenninger says."I'm extremely surprised by their results. " Says Alex Smith of the University of Guelph in Ontario, Canada. "It's a call to arms to keep doing the broad kind of genetic studies that we are doing. "Sampling as many individuals as possible, scientists hope to complete work on all fish and birds in another 5 to 10 years. Once either of these taxonomic groups is completed, Pfenninger says researchers will be able to decide how many cryptic species exist throughout the animal kingdom.Examples of cryptic species include the African elephant. A 2001 study found the elephants were actually two genetically distinct, non-interbreeding species, the African bush elephant and the African elephant. The species are currently listed as vulnerable and threatened, respectively, by the World Conservation Union (WCU).The reclassifications are more than an academic exercise. They define populations that have evolved independently of each other and whose genetic differences can have significant consequences. In the early 1900s misidentification of mosquito species based on morphology confused attempts to control malaria in Europe. Ultimately, what was thought to be a single species was actually made up of six sibling species, only three of which transmitted the disease. "The basic unit in biology is always the species, and you have to know what you are dealing with. " Pfenninger says. Much previous research is now no longer used, he says, because it is not clear what species was being studied.Which of the following about the significance of the research on cryptic species is NOT true?A．The results of the research can help the development of many other research areas.B．The results of the research can help the development of biodiversity estimates.C．The results of the research can help our understanding of infectious disease evolution.D．The results of the research can help our understanding of "survival of the fittest. "
Millions of people are in danger of getting malaria because______.A. some countries have not started a campaign against mosquitoesB. new species of mosquitoes may survive today's spraysC. malaria was once thought to be a very old evil of the worldD. present sprays are not as effective as people think
Passage OneAnimals have different ways of protecting themselves against wintertime weather. Some animals grow heavy coats of fur or feathers, while others dig into the ground to find a warm wintertime home.Some animals spend the winter in a deep sleep because by going to sleep they avoid the time of the year when food is scarce and the temperatures are low. Their sleep is known as hibernation.There is much about hibernation that puzzles scientists. For example, they are wondering how hibernation came into being. Some scientists have explored the possibility that animals release a chemical that starts them hibernating.One thing that scientists are certain about is that animals hibernate only when it is cold. Hibernation is a seasonal practice.Some animals that fall into a wintertime sleep are not true hibernators because they spend only a part of the cold season asleep. Bears, for example, can easily be awakened from their winter nap. They are not true hibernators.Sometimes it is difficult to determine whether a particular animal is a true hibernator. For example, some mice hibernate, but others do not. The same is true of bats. Some of them hibernate. Others do not.36. Hibernation is a seasonal practice. This means it ______.A. takes place only during a particular seasonB. occurs only during the nightC. is a daily practiceD. only happens when a species becomes over-populated
Time was when biologists somewhat over worded the evidence that these creatures preserve the health of game by killing the physically weak,or that they prey only on “worthless species。
Why is it a problem if all the smaller fish species die?A. It's not healthy for the environment.B. People only like to catch big fish.C. There are too many small fish.D. The smaller fish can get lost in the lake.
CDC considered the outbreak of West Nile in 1999 as a consequence of[A] the abolition of the mosquito-control programs.[B ] the surviving mosquito-borne infections.[C] the abuse of some $ 50 million in funds.[D] its failure to conquer mosquito-borne diseases.
Mr.Wang is the only one of the people here who ( )able to drive a truck. A、isB、can beC、areD、have been
— Were all three people in the car injured in the accident?— No, ______ only the two passengers who got hurt. A there isB it wereC there wasD it was
We must stress that this offer is firm for three days only because of the heavy demand () the limited supplies of this velvet in stock.A、forB、onC、ofD、in
The White Fountain inn will__________reservations only for parties of six people or more.A.aceeptB.acceptingC.aeceptedD.accepts
The White Fountain inn will __________reservations only for parties of six people or more.A.accept B.accepting C.accepted D.accepts
共用题干第二篇Human and the EarthIn terms of the evolution of life on Earth,human beings have just arrived.Despite their shori time on Earth,however,people have brought about enormous changes to the surface of the planet一changes far out of proportion to the interval of time they have occupied it.People have more control over their surroundings than any other species on Earth.With the combination of intelligence and manual skill(allowing us to make and use tools),people have found ways to use plant and animal resources,mineral ores,fuels,and many other materials and resources from the Earth.As the number of people on Earth increases,it becomes increasingly difficult for the population to survive on the resources of the land.The amount of land is limited.Although agricultural production can be increased by use of machinery such as tractors and the addition of fertilizer,the land ultimately can produce only so much food and no more.As the human population grows,people consume more.Clearly,some locations on Earth already have too many people;in many of these areas,future increases will surely bring about more poverty and suffering. Yet people in rich nations use proportionally far more of the available resources than people in poorer nations.As they consume these resources without restraint,they also waste large amounts of them.People are only a very small fraction of all the living things on the planet.Yet their numbers create a drain on resources that can't be renewed.For example,the amount of water on Earth is limited,this water is cleaned through natural processes.However,the natural processes for filtering water can clean only a certain amount of water by removing the pollution.Likewise,a limited amount of petroleum can be found under the Earth's surface.Petroleum is a valuable resource.Should people use it up to manufacture petrol for automobiles?As people work to control the planet and make life comfortable,are they using up resources that are needed for their survival?Why have people more control over their surroundings than any other species on Earth?A:Because of their intelligence and manual skill.B:Because they can use plant and animal resources,mineral ores and fuels.C:Because they are cleverer than any other animals on Earth.D:Both A and B.
At least how many tests were carried out by the scientists referred to in this passage A.ThreeB.TwoC.Only oneD.No one knows
Your database is up and running and one of your three control files is accidentally erased. You start RMAN and run the following command： RESTORE CONTROLFILE FROM AUTOBACKUP； Which of the following statements is true？（） A、 The command restores only the missing control file.B、 The command restores all the control files.C、 The command fails because the database is running.D、 This is the correct way to address this problem.E、 This is not the correct way to address this problem.
Which one of the following describes who will be able to see an existing doc that contains a readers field ?（）A、only those people listed in the access listB、anyone listed as a reader or above in the aclC、only those people list in the readers fieldD、anyone list as a reader or above in the acl and who is also list in the readers field
One of the tablespaces is read/x7fonly in your database. The loss of all control files forced you to re/x7fcreate the control file. Which operation do you need to perform after re/x7fcreating the control file and opening the database？（）A、drop and recreate the readonly tablespacesB、rename the readonly data files to their correct file namesC、change the tablespace status from read/write to readonlyD、recreate the readonly tablespace because it is automatically removed
Identify three correct statements of a multi-org setup. （）(Choose three.)A、A Government Reporting Entity (GRE)/Legal Entity can point to one and only one Set of Books.B、Inventory Orgs can be associated directly with a GRE/Legal Entity.C、The creation of a Master Inventory organization is mandatory.D、One and only one Operating Unit can be associated with a GRE/Legal Entity.E、One Set of Books can have one or many GRE's/Legal Entities associated with it.
多选题Your database is up and running and one of your three control files is accidentally erased. You start RMAN and run the following command： RESTORE CONTROLFILE FROM AUTOBACKUP； Which of the following statements is true？（）AThe command restores only the missing control file.BThe command restores all the control files.CThe command fails because the database is running.DThis is the correct way to address this problem.EThis is not the correct way to address this problem.
单选题One of the tablespaces is read-only in your database. The loss of all control files forced you to re-create the control file. Which operation do you need to perform after re-creating the control file and opening the database？（）A drop and re-create the read-only tablespacesB rename the read-only data files to their correct file namesC change the tablespace status from read/write to read-onlyD re-create the read-only tablespace because it is automatically removed
单选题Just-in-time inventory control systemAis adopted in most modern industries.Bis adopted only in very small company.Cis adopted only by some people.Dis adopted long long time ago.
单选题Although many people would not believe it, the mosquito is actually the most dangerous animal in Africa. While the bite of the black mamba is invariably lethal when untreated, this dreaded snake kills only a few dozen people per year. Hippopotami, with their immense strength and foul dispositions, kill hundreds of people per year in rivers and lakes, but the mosquito is still more dangerous. Mosquitoes bite hundreds of millions of people in Africa every year, and they infect over a million each year with malaria, a disease that is often fatal. Which of the following questions would be most useful in evaluating the claim made above regarding the mosquito?ACould a person survive an attack by a black mamba if that person received prompt medical attention?BWhat criteria are used to determine which animal is the “most dangerous” animal?CCould the incidence of mosquito bites be decreased through the judicious use of pesticides and insect repellent?DDoes malaria kill more people per year in Africa than tuberculosis?EHow does the percentage of people who survive hippopotamus attacks in Africa each year compare with the percentage of people who survive mosquito bites?
问答题In one day at a library, 64 people borrowed books. Twice as many people borrowed only a thriller as borrowed only a science fiction book. Three people borrowed a biography only and 11 people borrowed both science fiction and a thriller, but not a biography. The same number borrowed a biography and a thriller but no science fiction as borrowed one of each of the three types. Twenty-one people did not borrow a thriller. One more person borrowed a science fiction book and a biography book than borrowed a biography only. How many people borrowed a thriller only?
单选题Which of the following is NOT mentioned as a quality of email?AIt is a convenient communication tool.BIt allows conversations at different times.CIt is as easy to email a message to many people as to only one.DIt helps control social activities.
单选题If a mosquito were to bite a person. and that person were later to develop malaria and die of the disease, it is most likely that the person was infected with which of the following?AAnopheles gambiaeBAnopheles semiovaleCPlasmodium malariaeDPlastoodium vivaxEPlasmodium falciparum