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

Ex Input:
Single-celled organisms and multicellular organisms have this in common: both have a way to get rid of waste materials.

Ex Output:
Which characteristic do single-celled organisms and multicellular organisms have in common?

Ex Input:
If an air mass forms over an ocean it is called a maritime air mass.

Ex Output:
If an air mass forms over an ocean it is called what type of air mass?

Ex Input:
Collisions between hydrogen atoms demonstrate one form of nuclear fusion.

Ex Output:
Collisions between hydrogen atoms demonstrate one form of what?