TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
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: Glaciers deposit their sediment when they melt.

SOLUTION: When do glaciers deposit their sediment?

PROBLEM: Because of the wave character of matter, the idea of well-defined orbits gives way to a model in which there is a cloud of probability.

SOLUTION:
Because of the wave character of matter, the idea of well-defined orbits gives way to a model in which there is a cloud of what?