You are given a concept, and a list of answers. You should generate a question about the concept that leads to the given answer(s).
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Question: concept: Pepsi Center  answers:  ['Denver']

Answer: where is the pepsi center?


Question: concept: New England  answers:  ['Waltham']

Answer: when does summer start in new england?


Question: concept: J J Thomson  answers:  ['The electron in chemistry', 'Tendencies of recent investigations in the field of physics', 'Electricity and matter', 'Rays of positive electricity and their application to chemical analyses', 'Conduction of electricity through gases', 'The discharge of electricity through gases', 'Elements of the mathematical theory of electricity and magnetism', 'A treatise on the motion of vortex rings']

Answer:
what atom did j.j thomson discover?