2. 外语
  3. Researchers report that obesity relates to DNA. Some children get obese【C1】______they lack particular chunks of DNA, which kicks

Researchers report that obesity relates to DNA. Some children get obese【C1】______they lack particular chunks of DNA, which kicks

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问题     Researchers report that obesity relates to DNA. Some children get obese【C1】______they lack particular chunks of DNA, which kicks their hunger into overdrive.
    The British researchers【C2】______the DNA of 300 children who’d become very fat by age 10. They found【C3】______that several rare deletions may promote obesity, including one kind they found in【C4】______than 1% of about 1 200 severely obese children. That【C5】______, on chromosome (染色体) 16, apparently causes trouble because it【C6】______a gene that the brain needs to【C7】______to the appetite-controlling hormone leptin (瘦体素)， said Dr. Sadaf Farooqi of Cambridge University. Children with a chromosome 16 DNA deletion have a very strong【C8】______to eat.
    The work has already produced a real-world【C9】______Farooqi said four children with the chromosome 16 deletion had【C10】______drawn the attention of British child welfare authorities, who blamed the parents【C11】______overfeeding them. "We were able to【C12】______" and get the parents of two children off the hook, and the other two cases are【C13】______discussion, she said. That’s happened before the scientists uncovered【C14】______causes for severe childhood obesity, she said. "It’s a slightly【C15】______outcome of our research, but one we think is very important," she said.
   【C16】______scientists had previously discovered particular genes that promote obesity when damaged, the new work looked at【C17】______chunks of DNA that can span several genes.
    Eric Ravussin, an obesity expert, who wasn’t【C18】______in the study, said the work provides "a gold mine of information". That’s because it【C19】______specific chromosome areas that scientists can explore to【C20】______obesity-related genes, he said.
【C1】
选项 A、when
B、since
C、because
D、for
答案C
解析 逻辑关系题。本段提到染色体中缺乏某种DNA会导致食欲大增．进而导致肥胖。由此可知，肥胖和缺乏某种DNA模块之间是因果关系。because表因果关系，符合句意逻辑，为正确答案。when引导时间状语从句，不合句意，排除；since表原因时意为“既然”，强调该原因为具体事实；for也可表原因，但常指推断的原因。
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