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

Ex Input:
Clear mucus is secreted before ejaculation to neutralize acidic urine remaining in the urethra.

Ex Output:
What is secreted before ejaculation to neutralize acidic urine remaining in the urethra?


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

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


Ex Input:
The low atomic number of beryllium allows it to absorb x-rays.

Ex Output:
What aspect of beryllium allows it to absorb x-rays?