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

Ex Input:
If an air mass forms over an ocean it is called a maritime air mass.

Ex Output:
If an air mass forms over an ocean it is called what type of air mass?


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:
Prokaryotic cells have a cell wall outside their plasma membrane.

Ex Output:

Prokaryotic cells have what structure outside their plasma membrane?