TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: Most of the gray matter is on the surface of the brain, surrounding white matter.

SOLUTION: Most of the gray matter is on the surface of the brain, surrounding what other type of matter?

PROBLEM: The endocrine system produces hormones to regulate growth, development, and reproduction.

SOLUTION: Which human organ system produces hormones to regulate growth, development, and reproduction?

PROBLEM: Chemical sedimentary rocks forms when crystals precipitate out from a liquid.

SOLUTION:
What forms when crystals precipitate out from a liquid?