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阅读理解Researchers believe they have accurately estimated Antarctica's Weddell seal population for the first time—using images from space and the eyes of citizen scientists. Previous estimates of their population were "more back-of-the-envelope type calculations", said Dr. Michelle LaRue, a professor of New Zealand's University of Canterbury. "The previous research was done by traditional surveyors, but you can't physically get to the entire Antarctic continent all at one time," she said.The results were "inaccurate", so in 2016 LaRue created the first estimate of the seals' baseline population, using satellite imagery and the keen eyes of 330,000 curious volunteers. "We combined the imagery with a web platform to conduct a citizen science campaign to find out where seals are present, their abundance, and the environmental factors that influence their habitat preferences," LaRue said.They discovered that, at the time the satellite images were taken in 2021, the global population was actually just 40% of the 800,000 animals previously estimated. The study, published in late 2021, estimated that there were about 202,000 sub-adult and adult female Weddell seals in Antarctica. Male seals were generally not captured in the satellite images because they were typically under the ice, guarding their territories, LaRue added. The study also found that Weddell seals lived on about 1% of the ice and were picky about where they settled. The project relied heavily on volunteers to search the satellite images for signs of seals. Participants were given images of an area in Antarctica to scour and asked to tick a box saying if they believed they could see a seal or not. The more people to click yes, the more efficient the narrowing down of habitats became."The method is now being employed by other scientists to help determine the population of walrus(海象) in the Arctic," LaRue said, "Looking at broader ecosystems and the relationships between animals and their environment was important in the long run, but to do that, it was helpful to have population guides for single species." Once scientists have that information, they "can start adding it all together and putting together the puzzle a little bit better". （1） What is Paragraph 2 mainly about?  A . Limitation of previous studies. B . Significance of previous estimates. C . Inspiration for LaRue's research. D . Difficulty in exploring the Antarctica. （2） What does the underlined word "scour" in Paragraph 5 probably mean? A . Record. B . Appreciate. C . Examine. D . Post. （3） Walrus are mentioned in Paragraph 6 to present ____. A . a suggestion for follow-up studies. B . supporting evidence for the research results. C . an application of the research method. D . further explanations of the research methods. （4） What is the purpose of the text? A . To call for more research on counting seals. B . To introduce a breakthrough in seal research. C . To appeal to people to protect Weddell seals. D . To discuss the involvement of citizen scientists. 答案： A C C B

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