TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: The earth's magnetic poles have switched places repeatedly in the past.

SOLUTION: The earth's magnetic poles have done what repeatedly in the past?

PROBLEM: Exotic species are also called invasive species because they threaten other species.

SOLUTION: Why are exotic species also called invasive species?

PROBLEM: If an ecosystem's balance is disturbed by a volcanic eruption, the ecosystem will eventually become balanced again will most likely occur.

SOLUTION:
If an ecosystem's balance is disturbed by a volcanic eruption, what will most likely occur?