TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: Diffusion is the term for the movement of molecules from an area of high concentration to an area of low concentration.

SOLUTION: What is the term for the movement of molecules from an area of high concentration to an area of low concentration?

PROBLEM: Virtually all aquatic organisms depend directly or indirectly on protists for food.

SOLUTION: Virtually all aquatic organisms depend directly or indirectly on what for food?

PROBLEM: The mesopause is at the top of the mesosphere.

SOLUTION:
What is at the top of the mesosphere?