In this task, you are given a sentence and a question, you would be asked to create the answer which is contained in the sentence provided.

Sentence: The thick skin, found only on the palms of the hands and the soles of the feet, has an extra layer. Question: The thick skin, found only on the palms of the hands and the soles of the feet, has an extra what?
layer

Sentence: Weight is the force of gravity. Question: What is the force of gravity called?
weight

Sentence: The pion can only be created by violating the conservation of mass-energy. Question: The pion can only be created by violating the conservation of what?

mass-energy