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: Besides the Caucasus, what mountain range forms the border of Europe and Asia?

Answer: asia


Question: Which is the only Avril Lavigne song to have reached No.1 in the US Billboard Chart?

Answer: avril lavigne


Question: Angel, Itatinga, Cuquenan, Ormeli, and Tysse are all what?

Answer:
cuquenan falls