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

Ex Input:
A covalent network solid is a compound in which all of the atoms are connected to one another by covalent bonds.

Ex Output:
What is a compound in which all of the atoms are connected to one another by covalent bonds?


Ex Input:
Evolution occurs by natural selection, a process whereby better-adapted members pass along their traits, according to darwin.

Ex Output:
Evolution occurs by what process whereby better-adapted members pass along their traits, according to darwin?


Ex Input:
Inflammatory response is the second line of defense.

Ex Output:

What is the second line of defense?