TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: Compression zones is the opposite of rarefaction zones, where air molecules in waves are loosely packed.

SOLUTION: What is the opposite of rarefaction zones, where air molecules in waves are loosely packed?

PROBLEM: Gravity makes soil and rock particles move gradually down the slope during each thaw.

SOLUTION: What makes soil and rock particles move gradually down the slope during each thaw?

PROBLEM: The the core is the innermost layer of the sun.

SOLUTION:
What is the innermost layer of the sun called?