Sperm whales can produce stronger ultrasonic waves to kill their prey than dolphins.A．RightB．WrongC．Not mentioned
Sperm whales can produce stronger ultrasonic waves to kill their prey than dolphins.
A．Right
B．Wrong
C．Not mentioned
相关考题：
Smart WindowWindows not only let light in to cut down an electricity use for lighting, but the light coming through the window also provides heat. However, windows are not something people typically associate with being a cutting edge technology. Researchers are now working on new technologies that enable a window to quickly change from clear to dark and anywhere in between with a flip of a switch."It took us a long time to figure out what a window really is," says Claes Granqvist. He's a professor of solid-state physics at Uppsala University in Sweden. "It's contact with the outside world. You have to have visual contact with the surrounding world to feel well. " So, windows and natural light are important for improving the way people feel when they're stuck indoors.Yet, windows are the weak link in a building when it comes to energy and temperature control. In the winter, cold air leaks in. When it's hot and sunny, sunlight streams in. All of this sunlight carries lots of heat and energy. And all of this extra heat forces people to turn on their air conditioners. Producing blasts of cold air, which can feel so refreshing, actually suck up enormous amounts of electricity in buildings around the world.Windows have been a major focus of energy research for a long time. Over the years, scientists have come up with a variety of strategies for coating, glazing, and layering windows to make them more energy efficient. Smart windows go a step further. They use chromogenic technologies which involve changes of color.Electrochromic windows use electricity to change color. For example, a sheet of glass coated with thin layers of chemical compound such as tungsten oxide works a bit like a battery. Tungsten oxide is clear when an electric charge is applied and dark when the charge is removed, that is, when the amount of voltage is decreased, the window darkens until it's completely dark after all electricity is taken away. So applying a voltage determines whether the window looks clear or dark.One important feature that makes a smart window so smart is that it has a sort of "memory. " All it takes is a small jolt of voltage to turn the window from one state to the other. Then, it stays that way. Transitions take anywhere from 10 seconds to a few minutes, depending on the size of the window. The development of smart windows could mean that massive air conditioning systems may no longer need. "In the future," Granqvist says, "our buildings may look different. "Which of the following statements does not indicate the importance of windows as described in the first two paragraphs?A．Windows can change from clear to dark to save energy.B．Windows help to save energy by letting light in.C．Windows help to save energy by providing heat.D．Windows enable people to have contact with the outside world.
Crashed Cars to Text Message for HelpThere is no good place to have a car crash -- but some places are worse than others. In a foreign country, for instance,【51】 to explain via cellphone that you are upside down in a ditch (沟渠) when you cannot speak the local language can fatally (~) delay the arrival of the emergency services.But an answer may be at hand. Researchers funded by the European Commission are beginning tests of a system called E-merge that【52】senses when a ear has crashed and sends a text message, telling emergency services in the local language that the accident has taken place.The system was【53】 by ERTICO, a transport research organization based in Brussels. Belgium. Cars are fitted with a eellphone-sized device attached【54】 the underside of the dashboard (仪表板) which is activated by the same sensor that triggers the airbag in a crash. The device【55】 a cellphone circuit, a GPS positioning unit and a microphone and loudspeaker.It registers the severity of the crash by【56】 the deceleration data from the airbag's sensor. Using GPS information, it works out which country the Car is in, and from this it determines【57】 which language to compose an alert message detailing precise location of the accident.The device then automatically makes a call to the local emergency services【58】. If the car's occupants are conscious, they can communicate with the operator【59】 the speaker and microphone.E-merge also transmits the vehicles make, model, color and license number, and its heading' when it crashed, which in rum indicates on which side of a multi-lane highway it ended up.This【60】 the emergency services find the vehicle as soon as they arrive on the scene. "We can waste a large【61】time searching for an incident, "says Jim Hammond, a(an)【62】in vehicle technology at the Association of Chief Police Officers in the UK. Tests will begin soon with police car fleets in the UK. Trials have already started in Germany, Sweden, Spain, the Netherlands and Italy.In-car systems that summon (召集) the emergency services after a crash have【63】been fitted in some premium cars". ERTICO says that【64】EU states "are willing to fund the necessary infrastructure (基础结构), E--merge could be working by 2008.A study by French car maker Renault" concluded that the system could save up to 6000 of the 40,000 lives lost each year on Europe's roads, and prevent a similar number of serious injuries.The Renault study estimates that fitting E-merge to every car in Europe would eventually save around 150 billion per【65】in terms of reduced costs to health services and insurance companies, and fewer lost working days.(51)A．tryB．triedC．tryingD．having tried
"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. "
What was scientists' understanding of cryptic species?A．They occurred in equal numbers in all biogeographical regions.B．They were mostly found in insects and reptiles.C．They were likely to be in tropical rather than temperate regions.D．Both Ｂ and Ｃ.
Which of the following about the African bush elephant and the African elephant is true?A．The WCU are interbreeding those elephants.B．They are interbreeding species.C．They are two genetically distant species.D．They depend on each other for survival.
And the cars are tested for defects before leaving the factory.A．functionsB．faultsC．motionsD．parts
Which one of the following is NOT the reason for an overall lack of teaching Darwin's theory?A．Teaching of creationism diminishes teaching of evolution.B．Teachers are not required to teach Darwin's theory.C．teachers often leave out the teaching of evolution.D．Darwin's theory is denied as the central theory of biology.
AIBS's is composed of ______.A．more than 80 societies and 250,000 membersB．250,000 biologistsC．80 member organizationsD．more than 250,000 members and 80 member societies