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

Ex Input:
Some compounds form rigid frameworks called crystals.

Ex Output:
Some compounds form rigid frameworks called what?


Ex Input:
Most have cells that are not able to exchange gases with the outside environment do multicellular organisms need transport systems.

Ex Output:
Why do multicellular organisms need transport systems?


Ex Input:
When an ionic compound dissociates in water, water molecules surround each ion and separate it from the rest of the solid.

Ex Output:

When an ionic compound dissociates in water, water molecules surround each ion and separate it from the rest of the what?