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.

Q: Given Relationship: 'discover', Sentence: 'They were all established in Polynesia before Columbus discovered America , and hence could not have been introduced by later Spanish vessels .'

A: discovered
****
Q: Given Relationship: 'be city in', Sentence: 'The Early Renaissance began in the city of Florence in Central Italy in the fourteenth century .'

A: city
****
Q: Given Relationship: 'serve as', Sentence: 'While at the NSF he also served for two years in the Office of Science and Technology Policy in the Executive Office of the President as an NSF agency representative .'

A:
served
****