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: 'convert to', Sentence: 'After it converts ATP to ADP , the level of the latter accumulates outside the cell and the purine can bind to a purine receptor called P2Y1 .'

Answer: converts


Question: Given Relationship: 'be friend of', Sentence: 'I have always taken the position that Israel is a friend of the United States , and that friends should always stand up for one another , even in difficult times .'

Answer: friend


Question: Given Relationship: 'be daughter of', Sentence: 'Persephone was the daughter of Demeter and Zeus .'

Answer:
daughter