职称英语理工类AB级阅读理解精选练习(3)

　　Hidden Species May Be Surprisingly Common 　　Reports of cryptic species have increased dramatically over the past two decades with the advent of relatively inexpensive DNA sequencing technology. Mark Pfennninger and Klaus Schwenk, of the Goethe-Universitat in Frankfurts Germany, analyzed all known data on cryptic animal species aad discovered that they are found in equal proportions throughout all major branch, of the animal kingdom and occur in equal numbers in all biogeographical regions. 　　m extremely surprised by their results. says Alex Smith of the University of Guelph`Intririo. Canada. Its a call to arms to keep doing the broad kind of genetic studies that we are doing. 　　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. 　　In the early 1900s misidentification 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 hav to know what you are dealing with, Pfenninger said. Much previous research is now no longer used, he says, because it is not clear what species was studied. 　　A The results of the research can help the development of many other research areas: 　　C The results of the research can help our understanding of infectious disease evolution. 　　2. What was scientists understanding of cryptic species? 　　B They were mostly found in insects and reptiles. 　　D Both B and C 　　A Not yet. 　　C They will know the answer in another one or two years. 　　4. Which of the following about the African bush elephant and the African elephant is true? 　　B They are interbreeding species. 　　D They depend on each other for survival