instruction:
In this task, you are given a sentence and question which can be answered using the sentence. Your task is to answer the question using the information from the sentence. The answer to the question is unique and it is a continuous text span from the sentence.
question:
Sentence: The north tower was quickly rebuilt as a stubby , flat-roofed structure . 
 Question: how was something rebuilt?
answer:
quickly


question:
Sentence: Migrants to Belfast came from across Ireland , Scotland and England , but particularly from rural Ulster , where sectarian tensions ran deep . 
 Question: who   came  from somewhere?
answer:
Migrants to Belfast


question:
Sentence: When BrdU is integrated into DNA , it is supposed that the bromine deforms the minor groove so that Hoechst dyes can not reach their optimal binding site . 
 Question: what does something deform?
answer:

the minor groove