Given a fact, create a question that can be answered using the fact. Construct the question such that it is unambiguous, has a unique answer and the answer can be given using the fact.

Example Input: Fact: winter is when a hemisphere is tilted away from the sun
Example Output: What happens when a hemisphere is tilted away from the sun?

Example Input: Fact: if an animal eats another animal then that animal is a carnivore or omnivore or predator
Example Output: Which eats other creatures?

Example Input: Fact: when light enters the eye through the pupil , that light falls on the retina
Example Output:
A retina may be illuminated by?