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

[Q]: Compression zones is the opposite of rarefaction zones, where air molecules in waves are loosely packed.
[A]: What is the opposite of rarefaction zones, where air molecules in waves are loosely packed?


[Q]: Plasma matter makes up most of the universe.
[A]: What type of matter makes up most of the universe?


[Q]: The intermolecular structure of ice has spaces that are not present in liquid water.
[A]:
The intermolecular structure of what has spaces that are not present in liquid water?