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

Ex Input:
Light retains its original color under water because frequency remains the same when light is refracted.

Ex Output:
Light retains its original color under water because what remains the same when light is refracted?


Ex Input:
The high points in a transverse wave are called crests.

Ex Output:
What are the high points in a transverse wave called?


Ex Input:
Memory t cells are long-lived and can even persist for lifetime long.

Ex Output:
Memory t cells are long-lived and can even persist for how long?