Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

[EX Q]: Soft of these best describes the way a feather feels.
[EX A]: Which of these BEST describes the way a feather feels?

[EX Q]: Momentum is directly related to both mass and velocity.
[EX A]: Momentum is directly related to both mass and?

[EX Q]: Reptiles are a class of tetrapod vertebrates that produce amniotic eggs called.
[EX A]:
What are a class of tetrapod vertebrates that produce amniotic eggs called?