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

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

[EX Q]: The cytoskeleton holds cell organelles in place within the cytoplasm.
[EX A]: What part of the cell holds cell organelles in place within the cytoplasm?

[EX Q]: Hagfishes have a skull made of cartilage.
[EX A]:
Hagfishes have a skull made of what?