TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: Destructive interference in waves occurs two troughs what things overlap.

SOLUTION: Destructive interference in waves occurs when what things overlap?

PROBLEM: Filter feeders called rotifers collect digestive and excretory wastes in cloacal bladder primitive organ.

SOLUTION: Filter feeders called rotifers collect digestive and excretory wastes in what primitive organ?

PROBLEM: All cells have the small size in common.

SOLUTION:
What do all cells have in common?