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

Ex Input:
Plant nutrition is the study of the chemical elements necessary for plant growth.

Ex Output:
What is the study of the chemical elements necessary for plant growth called?


Ex Input:
The main advantage of urea is its very low toxicity.

Ex Output:
The main advantage of urea is its very low what?


Ex Input:
The pupil is the name of the black opening in the eye that lets light enter.

Ex Output:

What is the name of the black opening in the eye that lets light enter?