Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

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

A: Which system in the human body consists of the heart, a network of blood vessels, and blood?
****
Q: Antifreeze lowers it the freezing temperature of the water in car radiators.

A: What does antifreeze do to the freezing temperature of the water in car radiators?
****
Q: Metal conducts heat and electricity so well because of free flowing electrons.

A:
Why does metal conduct heat and electricity so well?
****