Definition: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

Positive Example 1 -
Input: Who was the first American President?
Output: president of the united states

Positive Example 2 -
Input: The Dutch duo of Ray Slijngaard and Anita Dels, who had 8 top ten hits in the 90s, were better known by what name?
Output: anita doth

Negative Example 1 -
Input: Anna Smashnova played which sport professionally until 2007?
Output: sport

Negative Example 2 -
Input: Rob Davis, Les Gray, Dave Mount and Ray Stiles are members of which pop group?
Output: david

Now complete the following example -
Input: Whose famous books include The Descent of Man, and Selection in Relation to Sex, The Expression of Emotions in Man and Animals,  The Power of Movement in Plants and The Formation of Vegetable Mould Through the Action of Worms?

Output: the power of movement in plants, natural selection, the expression of the emotions in man and animals, the formation of vegetable mould through the action of worms, the descent of man, and selection in relation to sex