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

Glaciers deposit their sediment when they melt.
When do glaciers deposit their sediment?

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?

3 many elements are in the compound mg(oh)2.
How many elements are in the compound Mg(OH)2?