instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
When light passes from one medium to another, it changes speed.
answer:
When light passes from one medium to another, it changes what?


question:
Prostate is the most common type of cancer in adult males.
answer:
What is the most common type of cancer in adult males?


question:
Depth and density influence the pressure of fluids.
answer:

What two factors influence the pressure of fluids?