TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: You call materials that have high resistance to electric current electric insulators.

SOLUTION: What do you call materials that have high resistance to electric current?

PROBLEM: If two populations do not mate and produce fertile offspring, separate species result.

SOLUTION: If two populations do not mate and produce fertile offspring, what results?

PROBLEM: Overharvesting is a serious threat particularly to aquatic species.

SOLUTION:
Overharvesting is a serious threat particularly to which species?