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

[Q]: Compounds containing an atom of nitrogen element, bonded in a hydrocarbon framework, are classified as amines.
[A]: Compounds containing an atom of what element, bonded in a hydrocarbon framework, are classified as amines?


[Q]: Collision frequency is greater for homogeneous category of catalysts, which also tend to be more sensitive to temperature and more 'expensive'.
[A]: Collision frequency is greater for what category of catalysts, which also tend to be more sensitive to temperature and more 'expensive'?


[Q]: The earliest known mammal fossils are from early jurassic period.
[A]:
The earliest known mammal fossils are from which period?