From the given sentence, extract the phrase (often noun or verb) that carries the given relationship. The generated phrase should be present in the sentence.
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Question: Given Relationship: 'be service of', Sentence: 'See a list of publications by Mayo Clinic authors on mitral valve disease on PubMed , a service of the National Library of Medicine .'

Answer: service


Question: Given Relationship: 'be cause of', Sentence: 'The founder of Alive and Well Los Angeles has been on many TV shows promoting the fact that HIV is not the cause of AIDS .'

Answer: cause


Question: Given Relationship: 'discover', Sentence: 'When Christopher Columbus ewly discovered America in 1492 , he was under the mistaken impression that he had found the western sea passage from Europe to India .'

Answer:
discovered