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]: The pupil is the name of the black opening in the eye that lets light enter.
[A]: What is the name of the black opening in the eye that lets light enter?


[Q]: The mouth is the first digestive organ that food enters.
[A]:
What is the first digestive organ that food enters?