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

The frequency of a wave is the reciprocal of the period of the wave.
The frequency of a wave is the reciprocal of what other attribute of the wave?

Saturated hydrocarbons hydrocarbons contain only single bonds between carbon atoms.
What hydrocarbons contain only single bonds between carbon atoms?

The neocortex is the unique layer of nerve cells covering the cerebrum in mammals' brains called.

What is the unique layer of nerve cells covering the cerebrum in mammals' brains called?