Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
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Question: Kronos (or Cronus) was the Greek equivalent of which Roman god?

Answer: cronus


Question: Feb 15, 1564 saw the birth of what famed Italian physicist, mathematician, astronomer, and philosopher, who discovered the first 4 moons of Jupiter?

Answer: astronomer


Question: Which actor played Barnes Wallis in the film The Dambusters?

Answer:
the dam busters