TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: A fewer predators is most likely to cause the number of rabbits living in an area to increase.

SOLUTION: Which factor is most likely to cause the number of rabbits living in an area to increase?

PROBLEM: The cardiovascular system in the human body consists of the heart, a network of blood vessels, and blood.

SOLUTION: Which system in the human body consists of the heart, a network of blood vessels, and blood?

PROBLEM: The earth's continental crust, on average, is 35 kilometers thick.

SOLUTION:
How thick is the earth's continental crust, on average?