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

Ex Input:
After fertilization, a zygote forms into two cells.

Ex Output:
After fertilization, how many cells does a zygote form into?


Ex Input:
A change of season and less food usually cause certain animals to migrate.

Ex Output:
Which two environmental changes usually cause certain animals to migrate?


Ex Input:
Degree of dna coiling determines the length and thickness of dna chromosomes.

Ex Output:

What determines the length and thickness of dna chromosomes?