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

Input: Consider Input: Carbon dioxide is an example of a material that easily undergoes sublimation.

Output: Carbon dioxide is an example of a material that easily undergoes what?


Input: Consider Input: Rod is the general shape of centrioles.

Output: What is the general shape of centrioles?


Input: Consider Input: When the helium is gone, the stars become white dwarfs.
Output: When the helium is gone, the stars become what?