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Q: Given Relationship: 'be region in', Sentence: 'The government of Chad has withdrawn from the African Union-brokered peace talks on Sudan 's troubled Darfur region .'

A: region
****
Q: Given Relationship: 'discover', Sentence: 'School children throughout the United States and Canada will tell you that Christopher Columbus discovered America when he was searching for a faster , more efficient route to the riches of India .'

A: discovered
****
Q: Given Relationship: 'be head of', Sentence: 'The head of the International Atomic Energy Agency , Mohamed ElBaradei , has told US diplomats that developing new weapons could encourage other countries to violate the nuclear non-proliferation treaty .'

A:
head
****