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

Input: Consider Input: The bird ancestor that lived in trees developed wings, which is commonly associated with birds.

Output: The bird ancestor that lived in trees developed what feature commonly associated with birds?

Input: Consider Input: Atoms of metals are good conductors of electricity because they give up electrons.

Output: Why are atoms of metals good conductors of electricity?

Input: Consider Input: Correlation is the comparison of two factors within a population.
Output: What is the comparison of two factors within a population?